Is it possible to have a zero price (free) Fixed Price Services in Complex Orders?

Oracle EBS 12.2.11 PO
On a Complex Purchase Order that primarily specifies Goods, the requirement is to also be able to specify and track services that are being provided free of charge. When specifying Fixed Price Service with a Lump Sum Pay Item, the system generates a "must enter positive value" error when 0 amount is entered.

The Fixed Price Service line is coming from the Requisition and being awarded into the Order so it is not possible to delete the Order line and recreate it as that orphans the requisition line. We don't want to omit the free services from the Order because they are being tracked and need to be performed.