Non-serialized items are getting expired when returned

The Install Base Sub Transaction Type 'Return For Replacement' has the status defined as 'Return For Replacement'.  This transaction type was used for a RMA line in Order Management.  After returning the non-serialized item to Inventory the corresponding Customer Product Instance in Install Base was end dated updated with a status of EXPIRED. Why was this instance expired instead of updating to a status of 'Return For Replacement' as set in the Install Base Sub Transaction Type definition?