The Subscription Billing-Revenue Allocation needs to support combining Non-Revenue Allocation Sales Orders (SO) and Revenue Allocation Sales Orders into a single SO Invoice.

Currently, the Subscription Billing-Revenue Allocation does not support this functionality. The system will display an error message in the following scenario:

1. Create two sales orders, one with Revenue Allocation and the other without.
2. Create a single invoice that includes both sales orders and set the Summary update for the Invoice Account.