diff --git a/gnucash/report/business-reports/customer-summary.scm b/gnucash/report/business-reports/customer-summary.scm
index e92b594e85..2ba1f71b8c 100644
--- a/gnucash/report/business-reports/customer-summary.scm
+++ b/gnucash/report/business-reports/customer-summary.scm
@@ -292,9 +292,7 @@
          (expense-accounts (opt-val pagename-expenseaccounts optname-expenseaccounts))
          (sales-accounts (opt-val pagename-incomeaccounts optname-incomeaccounts))
          (all-accounts (append sales-accounts expense-accounts))
-         (commodities (delete-duplicates
-                       (map xaccAccountGetCommodity all-accounts)
-                       gnc-commodity-equiv))
+         (commodities (gnc:accounts-get-commodities all-accounts #f))
          (commodities>1? (> (length commodities) 1))
          (book (gnc-get-current-book))
          (date-format (gnc:options-fancy-date book))
diff --git a/gnucash/report/standard-reports/balance-forecast.scm b/gnucash/report/standard-reports/balance-forecast.scm
index 2462c751a9..aa0a2680fb 100644
--- a/gnucash/report/standard-reports/balance-forecast.scm
+++ b/gnucash/report/standard-reports/balance-forecast.scm
@@ -167,8 +167,7 @@ date point, a projected minimum balance including scheduled transactions."))
           (accum (gnc:make-commodity-collector))
           (exchange-fn (gnc:case-exchange-time-fn
                         price currency
-                        (delete-duplicates! (map xaccAccountGetCommodity accounts)
-                                            gnc-commodity-equiv)
+                        (gnc:accounts-get-commodities accounts #f)
                         to-date #f #f))
           (accounts-balancelist
            (map
diff --git a/gnucash/report/standard-reports/balsheet-pnl.scm b/gnucash/report/standard-reports/balsheet-pnl.scm
index 2dbadf1eb1..6ad0a19a6a 100644
--- a/gnucash/report/standard-reports/balsheet-pnl.scm
+++ b/gnucash/report/standard-reports/balsheet-pnl.scm
@@ -802,12 +802,7 @@ also show overall period profit & loss."))
          ;; missing price, say so.
          (get-exchange-rates-fn
           (lambda (accounts col-idx)
-            (let ((commodities (delete
-                                common-currency
-                                (delete-duplicates
-                                 (map xaccAccountGetCommodity accounts)
-                                 gnc-commodity-equal)
-                                gnc-commodity-equal))
+            (let ((commodities (gnc:accounts-get-commodities accounts common-currency))
                   (cell (gnc:make-html-text)))
               (for-each
                (lambda (commodity)
diff --git a/gnucash/report/standard-reports/category-barchart.scm b/gnucash/report/standard-reports/category-barchart.scm
index 43ba7acb28..5de9ce386f 100644
--- a/gnucash/report/standard-reports/category-barchart.scm
+++ b/gnucash/report/standard-reports/category-barchart.scm
@@ -375,8 +375,7 @@ developing over time"))
                                 (xaccSplitGetAmount s))))))))
              ;; all selected accounts (of report-specific type), *and*
              ;; their descendants (of any type) need to be scanned.
-             (delete-duplicates
-              (append accounts (gnc:acccounts-get-all-subaccounts accounts)))))
+             (gnc:accounts-and-all-descendants accounts)))
 
           ;; Creates the <balance-list> to be used in the function
           ;; below.
diff --git a/gnucash/report/standard-reports/daily-reports.scm b/gnucash/report/standard-reports/daily-reports.scm
index 4e5203fb0e..c836fa39a2 100644
--- a/gnucash/report/standard-reports/daily-reports.scm
+++ b/gnucash/report/standard-reports/daily-reports.scm
@@ -226,21 +226,9 @@
           ;; add accounts to the query (include subaccounts 
           ;; if requested)
 	  (gnc:report-percent-done 25)
-          (if dosubs? 
-              (let ((subaccts '()))
-                (for-each 
-                 (lambda (acct)
-                   (let ((this-acct-subs 
-                          (gnc-account-get-descendants-sorted acct)))
-                     (if (list? this-acct-subs)
-                         (set! subaccts 
-                               (append subaccts this-acct-subs)))))
-                 accounts)
-                ;; Beware: delete-duplicates is an O(n^2)
-                ;; algorithm. More efficient method: sort the list,
-                ;; then use a linear algorithm.
-                (set! accounts
-                      (delete-duplicates (append accounts subaccts)))))
+          (if dosubs?
+              (set! accounts
+                (gnc:accounts-and-all-descendants accounts)))
 	  (gnc:report-percent-done 30)
           
           (xaccQueryAddAccountMatch query accounts QOF-GUID-MATCH-ANY QOF-QUERY-AND)