Invoicing plan not allowed, as service lines exist with FAA indicator

What causes this issue?

You want to create an invoicing plan for a service item for which you do
not expect a goods receipt. You have also set the <DS:DE.AA_FINAL_IND>
final account assignment indicator</> for at least one account
assignment item of the service line.

System Response

This is an error message. The system does not allow you to create an
invoicing plan.

How to fix this error?

You can only settle the service item with an invoicing plan if you first
deselect the final account assignment indicator for all account
assignment items of the service line.
<ZH>Note</>: If you have created an invoicing plan for a service item,
you can no longer set the final account assignment indicator for any of
its account assignment items.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.