for OM-SMC integration Creating RMA for Subscription enabled line it is asking for return receipt

Hi Team

I have to create RMA for Subscription Item for the line already interfaced to SMC and Billed to AR. while creating RMA in Order Management for Subscription line, assigned the orchestration DOO_SubscriptionReturnOrderProcess and for all the line type this is initiating the same workflow and return receipt will be required. Since this item is not associated with any inventory org being service subscription item, require warehouse and return receipt to execute the RMA Order.

Why the return receipt is require for subscription item. Looking for response.

Note: subscription item is not inventory org enabled item and item is assigned to only Item org.