Subcontracting QTY vs Assembly QTY

We are a job shop manufacturing company and have run into quite a few issues with subcontracting qty vs assembly qty.
For example, we may make a job for a customer that is qty 2 but when we send to the subcontractor, we may only need to send 1. We are able to get the purchase order correct with some manual communication but the issue it is causing is surrounding scheduling. The sub contracting operation does not get marked complete because we are only receiving qty 1 which matches the purchase order but does not seem to satisfy the job qty.
Does anyone have anything similar and how did you handle?

Taylor,

I am not sure if this helps, but maybe you can split jobs with 1 qty each and then link PO to respective jobs. Did you tried that already? So, once you receive them the job might be marked as completed.