diff --git a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.hpp b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.hpp
index f2da16710..e8394dcd0 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.hpp
@@ -42,10 +42,12 @@ public:
     struct AssignRecord {
         std::vector<std::string> selector;
         double value;
+        std::size_t report_step;
 
         bool operator==(const AssignRecord& data) const {
             return selector == data.selector &&
-                   value == data.value;
+                report_step == data.report_step &&
+                      value == data.value;
         }
 
         template<class Serializer>
@@ -53,19 +55,21 @@ public:
         {
             serializer(selector);
             serializer(value);
+            serializer(report_step);
         }
     };
 
     UDQAssign();
-    UDQAssign(const std::string& keyword, const std::vector<std::string>& selector, double value);
+    UDQAssign(const std::string& keyword, const std::vector<std::string>& selector, double value, std::size_t report_step);
 
     static UDQAssign serializeObject();
 
     const std::string& keyword() const;
     UDQVarType var_type() const;
-    void add_record(const std::vector<std::string>& selector, double value);
+    void add_record(const std::vector<std::string>& selector, double value, std::size_t report_step);
     UDQSet eval(const std::vector<std::string>& wells) const;
     UDQSet eval() const;
+    std::size_t report_step() const;
 
     bool operator==(const UDQAssign& data) const;
 
diff --git a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.hpp b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.hpp
index 8552a7664..1e787542b 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.hpp
@@ -53,10 +53,10 @@ namespace Opm {
         const std::string& unit(const std::string& key) const;
         bool has_unit(const std::string& keyword) const;
         bool has_keyword(const std::string& keyword) const;
-        void add_record(const DeckRecord& record);
+        void add_record(const DeckRecord& record, std::size_t report_step);
 
         void add_unit(const std::string& keyword, const std::string& unit);
-        void add_assign(const std::string& quantity, const std::vector<std::string>& selector, double value);
+        void add_assign(const std::string& quantity, const std::vector<std::string>& selector, double value, std::size_t report_step);
         void add_define(const std::string& quantity, const std::vector<std::string>& expression);
 
         void eval(std::size_t report_step, SummaryState& st, UDQState& udq_state) const;
@@ -96,6 +96,8 @@ namespace Opm {
 
     private:
         void add_node(const std::string& quantity, UDQAction action);
+        UDQAction action_type(const std::string& udq_key) const;
+
 
         UDQParams udq_params;
         UDQFunctionTable udqft;
diff --git a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.hpp b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.hpp
index fbc3e4889..6ff94712d 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.hpp
@@ -42,7 +42,8 @@ namespace Opm {
         std::optional<double> get_well_var(const std::string& well, const std::string& var) const;
         std::optional<double> get_group_var(const std::string& group, const std::string& var) const;
         void add(const std::string& key, double value);
-        void update(const std::string& keyword, const UDQSet& udq_result);
+        void update_assign(std::size_t report_step, const std::string& keyword, const UDQSet& udq_result);
+        void update_define(const std::string& keyword, const UDQSet& udq_result);
         const UDQFunctionTable& function_table() const;
         std::vector<std::string> wells() const;
         std::vector<std::string> groups() const;
diff --git a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.hpp b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.hpp
index 30bc01052..599e4c973 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.hpp
@@ -39,15 +39,19 @@ public:
     double get(const std::string& key) const;
     double get_group_var(const std::string& well, const std::string& var) const;
     double get_well_var(const std::string& well, const std::string& var) const;
-    void add(const std::string& udq_key, const UDQSet& result);
+    void add_define(const std::string& udq_key, const UDQSet& result);
+    void add_assign(std::size_t report_step, const std::string& udq_key, const UDQSet& result);
+    bool assign(std::size_t report_step, const std::string& udq_key) const;
 
     std::vector<char> serialize() const;
     void deserialize(const std::vector<char>& buffer);
     bool operator==(const UDQState& other) const;
 private:
+    void add(const std::string& udq_key, const UDQSet& result);
     double get_wg_var(const std::string& well, const std::string& key, UDQVarType var_type) const;
     double undefined_value;
     std::unordered_map<std::string, UDQSet> values;
+    std::unordered_map<std::string, std::size_t> assignments;
 };
 }
 
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/Schedule.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/Schedule.cpp
index cd6f2b892..ae0ab02d4 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/Schedule.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/Schedule.cpp
@@ -1389,7 +1389,7 @@ Schedule::Schedule(const Deck& deck, const EclipseState& es, const ParseContext&
         const auto& current = *this->udq_config.get(currentStep);
         std::shared_ptr<UDQConfig> new_udq = std::make_shared<UDQConfig>(current);
         for (const auto& record : keyword)
-            new_udq->add_record(record);
+            new_udq->add_record(record, currentStep);
 
         this->udq_config.update(currentStep, new_udq);
     }
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.cpp
index 27ef0827d..febabf909 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQAssign.cpp
@@ -27,11 +27,11 @@ UDQAssign::UDQAssign() :
 {
 }
 
-UDQAssign::UDQAssign(const std::string& keyword, const std::vector<std::string>& selector, double value) :
+UDQAssign::UDQAssign(const std::string& keyword, const std::vector<std::string>& selector, double value, std::size_t report_step) :
     m_keyword(keyword),
     m_var_type(UDQ::varType(keyword))
 {
-    this->add_record(selector, value);
+    this->add_record(selector, value, report_step);
 }
 
 UDQAssign UDQAssign::serializeObject()
@@ -39,13 +39,13 @@ UDQAssign UDQAssign::serializeObject()
     UDQAssign result;
     result.m_keyword = "test";
     result.m_var_type = UDQVarType::CONNECTION_VAR;
-    result.records = {{{"test1"}, 1.0}};
+    result.records = {{{"test1"}, 1.0, 0}};
 
     return result;
 }
 
-void UDQAssign::add_record(const std::vector<std::string>& selector, double value) {
-    this->records.push_back({selector, value});
+void UDQAssign::add_record(const std::vector<std::string>& selector, double value, std::size_t report_step) {
+    this->records.push_back({selector, value, report_step});
 }
 
 const std::string& UDQAssign::keyword() const {
@@ -56,6 +56,12 @@ UDQVarType UDQAssign::var_type() const {
     return this->m_var_type;
 }
 
+
+std::size_t UDQAssign::report_step() const {
+    return this->records.back().report_step;
+}
+
+
 UDQSet UDQAssign::eval(const std::vector<std::string>& wells) const {
     if (this->m_var_type == UDQVarType::WELL_VAR) {
         UDQSet ws = UDQSet::wells(this->m_keyword, wells);
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.cpp
index 84b84069b..b2868f267 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.cpp
@@ -22,6 +22,7 @@
 #include <opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQConfig.hpp>
 #include <opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQEnums.hpp>
 #include <opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQInput.hpp>
+#include <opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.hpp>
 
 namespace Opm {
 
@@ -75,13 +76,13 @@ namespace Opm {
             index_iter->second.action = action;
     }
 
-    void UDQConfig::add_assign(const std::string& quantity, const std::vector<std::string>& selector, double value) {
+    void UDQConfig::add_assign(const std::string& quantity, const std::vector<std::string>& selector, double value, std::size_t report_step) {
         this->add_node(quantity, UDQAction::ASSIGN);
         auto assignment = this->m_assignments.find(quantity);
         if (assignment == this->m_assignments.end())
-            this->m_assignments.insert( std::make_pair(quantity, UDQAssign(quantity, selector, value )));
+            this->m_assignments.insert( std::make_pair(quantity, UDQAssign(quantity, selector, value, report_step )));
         else
-            assignment->second.add_record(selector, value);
+            assignment->second.add_record(selector, value, report_step);
     }
 
 
@@ -113,12 +114,12 @@ namespace Opm {
           keyword.
         */
         if (!this->has_keyword(keyword))
-            this->add_assign(keyword, {}, 0);
+            this->add_assign(keyword, {}, 0, 0);
         this->units[keyword] = unit;
     }
 
 
-    void UDQConfig::add_record(const DeckRecord& record) {
+    void UDQConfig::add_record(const DeckRecord& record, std::size_t report_step) {
         auto action = UDQ::actionType(record.getItem("ACTION").get<RawString>(0));
         const auto& quantity = record.getItem("QUANTITY").get<std::string>(0);
         const auto& data = RawString::strings( record.getItem("DATA").getData<RawString>() );
@@ -132,7 +133,7 @@ namespace Opm {
             if (action == UDQAction::ASSIGN) {
                 std::vector<std::string> selector(data.begin(), data.end() - 1);
                 double value = std::stod(data.back());
-                this->add_assign(quantity, selector, value);
+                this->add_assign(quantity, selector, value, report_step);
             } else if (action == UDQAction::DEFINE)
                 this->add_define(quantity, data);
             else
@@ -144,13 +145,18 @@ namespace Opm {
         return this->m_definitions.at(key);
     }
 
+    UDQAction UDQConfig::action_type(const std::string& udq_key) const {
+        auto action_iter = this->input_index.find(udq_key);
+        return action_iter->second.action;
+    }
 
     std::vector<UDQDefine> UDQConfig::definitions() const {
         std::vector<UDQDefine> ret;
 
-        for (const auto& key : this->define_order)
-            ret.push_back(this->m_definitions.at(key));
-
+        for (const auto& key : this->define_order) {
+            if (this->action_type(key) == UDQAction::DEFINE)
+                ret.push_back(this->m_definitions.at(key));
+        }
         return ret;
     }
 
@@ -159,7 +165,7 @@ namespace Opm {
         std::vector<UDQDefine> filtered_defines;
         for (const auto& key : this->define_order) {
             const auto& udq_define = this->m_definitions.at(key);
-            if (udq_define.var_type() == var_type)
+            if (udq_define.var_type() == var_type && this->action_type(key) == UDQAction::DEFINE)
                 filtered_defines.push_back(udq_define);
         }
         return filtered_defines;
@@ -210,16 +216,16 @@ namespace Opm {
 
 
     std::vector<UDQAssign> UDQConfig::assignments(UDQVarType var_type) const {
-        std::vector<UDQAssign> filtered_defines;
+        std::vector<UDQAssign> filtered_assigns;
         for (const auto& index_pair : this->input_index) {
-            if (index_pair.second.action == UDQAction::ASSIGN) {
-                const std::string& key = index_pair.first;
-                const auto& udq_define = this->m_assignments.at(key);
-                if (udq_define.var_type() == var_type)
-                    filtered_defines.push_back(udq_define);
+            const std::string& key = index_pair.first;
+            const auto& assign_iter = this->m_assignments.find(key);
+            if (assign_iter != this->m_assignments.end()) {
+                if (assign_iter->second.var_type() == var_type)
+                    filtered_assigns.push_back(assign_iter->second);
             }
         }
-        return filtered_defines;
+        return filtered_assigns;
     }
 
 
@@ -295,38 +301,44 @@ namespace Opm {
         UDQContext context(func_table, st, udq_state);
 
         for (const auto& assign : this->assignments(UDQVarType::WELL_VAR)) {
-            auto ws = assign.eval(st.wells());
-            context.update(assign.keyword(), ws);
-            st.update_udq(ws, undefined_value);
+            if (udq_state.assign(report_step, assign.keyword())) {
+                auto ws = assign.eval(st.wells());
+                context.update_assign(report_step, assign.keyword(), ws);
+                st.update_udq(ws, undefined_value);
+            }
         }
 
         for (const auto& def : this->definitions(UDQVarType::WELL_VAR)) {
             auto ws = def.eval(context);
-            context.update(def.keyword(), ws);
+            context.update_define(def.keyword(), ws);
             st.update_udq(ws, undefined_value);
         }
 
         for (const auto& assign : this->assignments(UDQVarType::GROUP_VAR)) {
-            auto ws = assign.eval(st.groups());
-            context.update(assign.keyword(), ws);
-            st.update_udq(ws, undefined_value);
+            if (udq_state.assign(report_step, assign.keyword())) {
+                auto ws = assign.eval(st.groups());
+                context.update_assign(report_step, assign.keyword(), ws);
+                st.update_udq(ws, undefined_value);
+            }
         }
 
         for (const auto& def : this->definitions(UDQVarType::GROUP_VAR)) {
             auto ws = def.eval(context);
-            context.update(def.keyword(), ws);
+            context.update_define(def.keyword(), ws);
             st.update_udq(ws, undefined_value);
         }
 
         for (const auto& assign : this->assignments(UDQVarType::FIELD_VAR)) {
-            auto ws = assign.eval();
-            context.update(assign.keyword(), ws);
-            st.update_udq(ws, undefined_value);
+            if (udq_state.assign(assign.report_step(), assign.keyword())) {
+                auto ws = assign.eval();
+                context.update_assign(report_step, assign.keyword(), ws);
+                st.update_udq(ws, undefined_value);
+            }
         }
 
         for (const auto& def : this->definitions(UDQVarType::FIELD_VAR)) {
             auto field_udq = def.eval(context);
-            context.update(def.keyword(), field_udq);
+            context.update_define(def.keyword(), field_udq);
             st.update_udq(field_udq, undefined_value);
         }
     }
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.cpp
index 4ea8fac60..8dfeffb20 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQContext.cpp
@@ -62,9 +62,6 @@ bool is_udq(const std::string& key) {
         this->add("TIME", 0.0);
     }
 
-    void UDQContext::update(const std::string& keyword, const UDQSet& udq_result) {
-        this->udq_state.add(keyword, udq_result);
-    }
 
     void UDQContext::add(const std::string& key, double value) {
         this->values[key] = value;
@@ -116,4 +113,12 @@ bool is_udq(const std::string& key) {
     const UDQFunctionTable& UDQContext::function_table() const {
         return this->udqft;
     }
+
+    void UDQContext::update_assign(std::size_t report_step, const std::string& keyword, const UDQSet& udq_result) {
+        this->udq_state.add_assign(report_step, keyword, udq_result);
+    }
+
+    void UDQContext::update_define(const std::string& keyword, const UDQSet& udq_result) {
+        this->udq_state.add_define(keyword, udq_result);
+    }
 }
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQDefine.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQDefine.cpp
index 94d17ee89..c548cc3a8 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQDefine.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQDefine.cpp
@@ -254,7 +254,7 @@ UDQSet UDQDefine::eval(UDQContext& context) const {
         std::string msg = "Invalid runtime type conversion detected when evaluating UDQ";
         throw std::invalid_argument(msg);
     }
-    context.update(this->keyword(), res);
+    context.update_define(this->keyword(), res);
 
     if (res.var_type() == UDQVarType::SCALAR) {
         /*
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.cpp
index adc4ef45f..657ebb1ea 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/UDQ/UDQState.cpp
@@ -82,6 +82,15 @@ void UDQState::add(const std::string& udq_key, const UDQSet& result) {
         res_iter->second = result;
 }
 
+void UDQState::add_define(const std::string& udq_key, const UDQSet& result) {
+    this->add(udq_key, result);
+}
+
+void UDQState::add_assign(std::size_t report_step, const std::string& udq_key, const UDQSet& result) {
+    this->assignments[udq_key] = report_step;
+    this->add(udq_key, result);
+}
+
 double UDQState::get(const std::string& key) const {
     if (!is_udq(key))
         throw std::logic_error("Key is not a UDQ variable:" + key);
@@ -125,6 +134,16 @@ bool UDQState::operator==(const UDQState& other) const {
            this->values == other.values;
 }
 
+
+
+bool UDQState::assign(std::size_t report_step, const std::string& udq_key) const {
+    auto assign_iter = this->assignments.find(udq_key);
+    if (assign_iter == this->assignments.end())
+        return true;
+    else
+        return report_step > assign_iter->second;
+}
+
 std::vector<char> UDQState::serialize() const {
     Serializer ser;
     ser.put(this->undefined_value);
@@ -133,7 +152,8 @@ std::vector<char> UDQState::serialize() const {
         ser.put( set_pair.first );
         set_pair.second.serialize( ser );
     }
-    return std::move(ser.buffer);
+    ser.put(this->assignments);
+    return ser.buffer;
 }
 
 
@@ -151,6 +171,7 @@ void UDQState::deserialize(const std::vector<char>& buffer) {
             this->values.insert( std::make_pair(key, udq_set) );
         }
     }
+    this->assignments = ser.get<std::string, std::size_t>();
 }
 }
 
diff --git a/tests/parser/UDQTests.cpp b/tests/parser/UDQTests.cpp
index 26afdbe72..2449c3cd9 100644
--- a/tests/parser/UDQTests.cpp
+++ b/tests/parser/UDQTests.cpp
@@ -942,9 +942,9 @@ BOOST_AUTO_TEST_CASE(UDQ_SET_DIV) {
 
 
 BOOST_AUTO_TEST_CASE(UDQASSIGN_TEST) {
-    UDQAssign as1("WUPR", {}, 1.0);
-    UDQAssign as2("WUPR", {"P*"}, 2.0);
-    UDQAssign as3("WUPR", {"P1"}, 4.0);
+    UDQAssign as1("WUPR", {}, 1.0, 1);
+    UDQAssign as2("WUPR", {"P*"}, 2.0, 2);
+    UDQAssign as3("WUPR", {"P1"}, 4.0, 3);
     std::vector<std::string> ws1 = {"P1", "P2", "I1", "I2"};
 
     auto res1 = as1.eval(ws1);
@@ -1455,7 +1455,7 @@ BOOST_AUTO_TEST_CASE(UDQ_USAGE) {
     BOOST_CHECK_EQUAL( usage.IUAD_size(), 0 );
 
     UDAValue uda1("WUX");
-    conf.add_assign(uda1.get<std::string>(), {}, 100);
+    conf.add_assign(uda1.get<std::string>(), {}, 100, 0);
 
     usage.update(conf, uda1, "W1", UDAControl::WCONPROD_ORAT);
     BOOST_CHECK_EQUAL( usage.IUAD_size(), 1 );
@@ -1842,12 +1842,12 @@ BOOST_AUTO_TEST_CASE(UDQSTATE) {
     BOOST_CHECK_THROW(st.get("FUPR"), std::out_of_range);
 
     auto fxpr = UDQSet::scalar("FXPR", 100);
-    BOOST_CHECK_THROW(st.add("FXPR", fxpr), std::logic_error);
+    BOOST_CHECK_THROW(st.add_define("FXPR", fxpr), std::logic_error);
 
     BOOST_CHECK_THROW(st.get_well_var("OP1", "WUPR"), std::out_of_range);
 
     auto fupr = UDQSet::scalar("FUPR", 100);
-    st.add("FUPR", fupr);
+    st.add_define("FUPR", fupr);
 
     // This is not a well quantity
     BOOST_CHECK_THROW(st.get_well_var("OP1", "FUPR"), std::logic_error);
@@ -1856,7 +1856,7 @@ BOOST_AUTO_TEST_CASE(UDQSTATE) {
 
     auto wupr = UDQSet::wells("WUPR", {"P1", "P2"});
     wupr.assign("P1", 75);
-    st.add("WUPR", wupr);
+    st.add_define("WUPR", wupr);
 
     BOOST_CHECK(st.has_well_var("P1", "WUPR"));
     // We have a well P2 - but we have not assigned a value to it!
@@ -1946,6 +1946,8 @@ DEFINE WUGASRA  750000 - WGLIR '*' /
 
 BOOST_AUTO_TEST_CASE(UDQ_UNDEFINED) {
     std::string deck_string = R"(
+SCHEDULE
+
 -- udq #2
 UDQ
 ----XX xxxx xxx
@@ -2129,15 +2131,13 @@ DEFINE FU_VAR91 GOPR TEST  /
     st.update_well_var("W1", "WGLIR", 1);
     st.update_well_var("W2", "WGLIR", 2);
     st.update_well_var("W3", "WGLIR", 3);
+    st.update_group_var("TEST", "GOPR", 1);
 
     udq.eval(0, st, udq_state);
-
-    // The current testcase has some ordering & defined / undefined issues which
 }
 
 
 
-
 BOOST_AUTO_TEST_CASE(UDQ_KEY_ERROR) {
     std::string deck_string = R"(
 -- udq #2
@@ -2156,3 +2156,85 @@ UDQ
 
     BOOST_CHECK_THROW(udq.eval(0, st, udq_state), std::out_of_range);
 }
+
+
+BOOST_AUTO_TEST_CASE(UDQ_ASSIGN) {
+    std::string deck_string = R"(
+-- udq #2
+SCHEDULE
+
+UDQ
+  ASSIGN FU_VAR1 5  /
+  DEFINE FU_VAR1 FU_VAR1 + 5 /
+/
+)";
+
+    auto schedule = make_schedule(deck_string);
+    const auto& udq = schedule.getUDQConfig(0);
+    auto undefined_value =  udq.params().undefinedValue();
+    UDQState udq_state(undefined_value);
+    SummaryState st(std::chrono::system_clock::now());
+
+    udq.eval(0, st, udq_state);
+    BOOST_CHECK_EQUAL(st.get("FU_VAR1"), 10);
+}
+
+BOOST_AUTO_TEST_CASE(UDQ_ASSIGN_REASSIGN) {
+    std::string deck_string = R"(
+-- udq #2
+SCHEDULE
+
+UDQ
+  ASSIGN FU_VAR1 0  /
+  DEFINE FU_VAR1 FU_VAR1 + 1 /
+/
+
+TSTEP
+   1 1 1 1 1 /
+
+UDQ
+  ASSIGN FU_VAR1 0  /
+  DEFINE FU_VAR1 FU_VAR1 + 1 /
+/
+
+TSTEP
+   1 1 1 1 1 /
+
+UDQ
+  ASSIGN FU_VAR1 0  /
+/
+
+TSTEP
+   1 1 1 1 1 /
+
+)";
+
+    auto schedule = make_schedule(deck_string);
+    UDQState udq_state(0);
+    SummaryState st(std::chrono::system_clock::now());
+
+    // Counting: 1,2,3,4,5
+    for (std::size_t report_step = 0; report_step < 5; report_step++) {
+        const auto& udq = schedule.getUDQConfig(report_step);
+        udq.eval(report_step, st, udq_state);
+        auto fu_var1 = st.get("FU_VAR1");
+        BOOST_CHECK_EQUAL(fu_var1, report_step + 1);
+    }
+
+    // Reset to zero and count: 1,2,3,4,5
+    for (std::size_t report_step = 5; report_step < 10; report_step++) {
+        const auto& udq = schedule.getUDQConfig(report_step);
+        udq.eval(report_step, st, udq_state);
+        auto fu_var1 = st.get("FU_VAR1");
+        BOOST_CHECK_EQUAL(fu_var1, report_step - 4);
+    }
+
+    // Reset to zero and stay there.
+    for (std::size_t report_step = 10; report_step < 15; report_step++) {
+        const auto& udq = schedule.getUDQConfig(report_step);
+        udq.eval(report_step, st, udq_state);
+        auto fu_var1 = st.get("FU_VAR1");
+        BOOST_CHECK_EQUAL(fu_var1, 0);
+    }
+}
+
diff --git a/tests/test_AggregateUDQData.cpp b/tests/test_AggregateUDQData.cpp
index 10f98db96..55f6a0a9a 100644
--- a/tests/test_AggregateUDQData.cpp
+++ b/tests/test_AggregateUDQData.cpp
@@ -87,32 +87,32 @@ Opm::UDQSet make_udq_set(const std::string& name, Opm::UDQVarType var_type, cons
     {
         auto state = Opm::UDQState{0};
 
-        state.add("WUOPRL", make_udq_set("WUOPRL",
-                                         Opm::UDQVarType::WELL_VAR,
-                                         {"PROD1", "PROD2", "WINJ1", "WINJ2"},
-                                         {210, 211, 212, 213}));
+        state.add_define("WUOPRL", make_udq_set("WUOPRL",
+                                                Opm::UDQVarType::WELL_VAR,
+                                                {"PROD1", "PROD2", "WINJ1", "WINJ2"},
+                                                {210, 211, 212, 213}));
 
-        state.add("WUOPRU", make_udq_set("WUOPRU",
-                                         Opm::UDQVarType::WELL_VAR,
-                                         {"PROD1", "PROD2", "WINJ1", "WINJ2"},
-                                         {220, 221, 222, 223}));
+        state.add_define("WUOPRU", make_udq_set("WUOPRU",
+                                                Opm::UDQVarType::WELL_VAR,
+                                                {"PROD1", "PROD2", "WINJ1", "WINJ2"},
+                                                {220, 221, 222, 223}));
 
-        state.add("WULPRL", make_udq_set("WULPRL",
-                                         Opm::UDQVarType::WELL_VAR,
-                                         {"PROD1", "PROD2", "WINJ1", "WINJ2"},
-                                         {230, 231, 232, 233}));
+        state.add_define("WULPRL", make_udq_set("WULPRL",
+                                                Opm::UDQVarType::WELL_VAR,
+                                                {"PROD1", "PROD2", "WINJ1", "WINJ2"},
+                                                {230, 231, 232, 233}));
 
-        state.add("WULPRU", make_udq_set("WULPRU",
-                                         Opm::UDQVarType::WELL_VAR,
-                                         {"PROD1", "PROD2", "WINJ1", "WINJ2"},
-                                         {160, 161, 162, 163}));
+        state.add_define("WULPRU", make_udq_set("WULPRU",
+                                                Opm::UDQVarType::WELL_VAR,
+                                                {"PROD1", "PROD2", "WINJ1", "WINJ2"},
+                                                {160, 161, 162, 163}));
 
-        state.add("GUOPRU", make_udq_set("GUOPRU",
-                                         Opm::UDQVarType::GROUP_VAR,
-                                         {"WGRP1", "WGRP2", "GRP1"},
-                                         {360, 361, 362}));
+        state.add_define("GUOPRU", make_udq_set("GUOPRU",
+                                                Opm::UDQVarType::GROUP_VAR,
+                                                {"WGRP1", "WGRP2", "GRP1"},
+                                                {360, 361, 362}));
 
-        state.add("FULPR", Opm::UDQSet::scalar("FULPR", 460));
+        state.add_define("FULPR", Opm::UDQSet::scalar("FULPR", 460));
         return state;
     }