Costing transactions for Depot Repair Ship Repaired Item (zero cost)

What is the best practice to handle inventory costing for shipped repaired items from Depot Repair in R12?  We ship new product item X out to customer and costing occurs as expected since the item attributes are set on for Costing.  Then the item is returned for repair and we create the RMA and Ship line automatically in Depot Repair.  When we ship the repaired item back we do not want the costed transactions created (at least not at the product cost)...should be at zero cost.  We do not charge for the product repaired only our separate repair parts / labor, etc.