diff --git a/ApplicationLibCode/Application/RiaPreferencesSummary.cpp b/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
index 4f1db5903f..81a09adf7a 100644
--- a/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
+++ b/ApplicationLibCode/Application/RiaPreferencesSummary.cpp
@@ -352,6 +352,7 @@ void RiaPreferencesSummary::defineEditorAttribute( const caf::PdmFieldHandle* fi
 //--------------------------------------------------------------------------------------------------
 void RiaPreferencesSummary::defineUiOrdering( QString uiConfigName, caf::PdmUiOrdering& uiOrdering )
 {
+    uiOrdering.add( &m_useMultipleThreadsWhenLoadingSummaryCases );
     uiOrdering.add( &m_summaryReader );
 
     if ( m_summaryReader == SummaryReaderMode::OPM_COMMON )
@@ -370,8 +371,6 @@ void RiaPreferencesSummary::defineUiOrdering( QString uiConfigName, caf::PdmUiOr
         }
     }
 
-    uiOrdering.add( &m_useMultipleThreadsWhenLoadingSummaryCases );
-
     uiOrdering.skipRemainingFields();
 }
 
diff --git a/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.cpp b/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.cpp
index 2461d3d069..e8c173f9d9 100644
--- a/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.cpp
+++ b/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.cpp
@@ -64,6 +64,9 @@ bool RifSummaryReaderMultipleFiles::values( const RifEclipseSummaryAddress& resu
             readerValues = zeros;
         }
 
+        auto valueCount = timeStepCount( reader.get() );
+        readerValues.resize( valueCount );
+
         values->insert( values->end(), readerValues.begin(), readerValues.end() );
     }
 
@@ -92,6 +95,20 @@ RiaDefines::EclipseUnitSystem RifSummaryReaderMultipleFiles::unitSystem() const
     return RiaDefines::EclipseUnitSystem::UNITS_UNKNOWN;
 }
 
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+size_t RifSummaryReaderMultipleFiles::timeStepCount( RifSummaryReaderInterface* reader ) const
+{
+    auto it = m_valueCountForReader.find( reader );
+    if ( it != m_valueCountForReader.end() )
+    {
+        return it->second;
+    }
+
+    return 0;
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
@@ -107,12 +124,11 @@ bool RifSummaryReaderMultipleFiles::createReadersAndImportMetaData( RiaThreadSaf
         }
     }
 
+    calculateOverlappingTimeSteps();
+
+    // Aggregate result addresses
     for ( const auto& reader : m_summaryReaders )
     {
-        auto readerTimeSteps = reader->timeSteps( {} );
-
-        m_aggregatedTimeSteps.insert( m_aggregatedTimeSteps.end(), readerTimeSteps.begin(), readerTimeSteps.end() );
-
         {
             auto resultAddresses = reader->allResultAddresses();
             m_allResultAddresses.insert( resultAddresses.begin(), resultAddresses.end() );
@@ -126,3 +142,48 @@ bool RifSummaryReaderMultipleFiles::createReadersAndImportMetaData( RiaThreadSaf
 
     return true;
 }
+
+//--------------------------------------------------------------------------------------------------
+///
+// Detect any overlapping time steps. Always use data from summary reader with the newest data, so do processing
+// from the last reader to the first
+//
+//--------------------------------------------------------------------------------------------------
+void RifSummaryReaderMultipleFiles::calculateOverlappingTimeSteps()
+{
+    if ( m_summaryReaders.empty() ) return;
+
+    auto lastRestartCase                   = m_summaryReaders.back().get();
+    auto lastRestartCaseTimeSteps          = lastRestartCase->timeSteps( {} );
+    m_valueCountForReader[lastRestartCase] = lastRestartCaseTimeSteps.size();
+
+    time_t cutOffTime = lastRestartCaseTimeSteps.front();
+    for ( int i = static_cast<int>( m_summaryReaders.size() - 2 ); i >= 0; i-- )
+    {
+        auto currentReader    = m_summaryReaders.at( static_cast<size_t>( i ) ).get();
+        auto currentTimeSteps = currentReader->timeSteps( {} );
+
+        size_t timeStepIndex = 0;
+        for ( auto t : currentTimeSteps )
+        {
+            if ( t < cutOffTime ) timeStepIndex++;
+        }
+
+        m_valueCountForReader[currentReader] = timeStepIndex;
+
+        if ( currentTimeSteps.front() < cutOffTime )
+        {
+            cutOffTime = currentTimeSteps.front();
+        }
+    }
+
+    // Create a vector of increasing time steps with no overlapping time steps
+    for ( const auto& reader : m_summaryReaders )
+    {
+        auto currentTimeSteps = reader->timeSteps( {} );
+        auto valueCount       = m_valueCountForReader[reader.get()];
+        currentTimeSteps.resize( valueCount );
+
+        m_aggregatedTimeSteps.insert( m_aggregatedTimeSteps.end(), currentTimeSteps.begin(), currentTimeSteps.end() );
+    }
+}
diff --git a/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.h b/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.h
index 17739594a3..b8e6d4b2d1 100644
--- a/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.h
+++ b/ApplicationLibCode/FileInterface/RifSummaryReaderMultipleFiles.h
@@ -44,9 +44,14 @@ public:
     std::string unitName( const RifEclipseSummaryAddress& resultAddress ) const override;
     RiaDefines::EclipseUnitSystem unitSystem() const override;
 
+private:
+    size_t timeStepCount( RifSummaryReaderInterface* reader ) const;
+    void   calculateOverlappingTimeSteps();
+
 private:
     std::vector<std::string>                                m_fileNames;
     std::vector<std::unique_ptr<RifSummaryReaderInterface>> m_summaryReaders;
 
-    std::vector<time_t> m_aggregatedTimeSteps;
+    std::map<RifSummaryReaderInterface*, size_t> m_valueCountForReader;
+    std::vector<time_t>                          m_aggregatedTimeSteps;
 };