killbill-memoizeit

diff --git a/invoice/src/main/java/com/ning/billing/invoice/generator/DefaultInvoiceGenerator.java b/invoice/src/main/java/com/ning/billing/invoice/generator/DefaultInvoiceGenerator.java
index 7397f07..a1115be 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/generator/DefaultInvoiceGenerator.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/generator/DefaultInvoiceGenerator.java
@@ -409,7 +409,7 @@ public class DefaultInvoiceGenerator implements InvoiceGenerator {
                 iterator.remove();
             }
         }
-        existingItems.addAll(itemsToAdd);
+        proposedItems.addAll(itemsToAdd);
     }