No Charge Replacement Parts in Service w/ fifo

Multiple vendors that we work with send “no charge” warranty replacement parts that associate with open Service Order & Appointments in Acumatica. My instinct in Acumatica is to create a Zero $ purchase order from the service order and once the parts arrive enter a receipt to match.

My challenge is that Fifo layers don’t play nice with this circumstance and the first available layer is what posts to the document when it is invoiced. I need the parts ordered on PO for these jobs to be reflected in the Service Order/Appointment at $0.

Any ideas on how to achieve this outcome? I considered using a non stock item with the applicable part #, but then I lose the benefit of issue reports and adjusting my replenishment to keep up with demand.