If the Order Type on the main tab is Drop Ship it ignores received quantity when evaluating whether or not to close. If you need to "force" a PO to close because it's a short you can either invoice the remaining quantity at a cost of 0 or delete the purchase order. 

If the Order Type on the main tab is Drop Ship it ignores received quantity when evaluating whether or not to close. If you need to "force" a PO to close because it's a short you can either invoice the remaining quantity at a cost of 0 or delete the purchase order. 

If they delete the PO, and ever want to know what was on it, I don't see a report/function that will let them do that.  Or am I overlooking some feature in the system?

This is v2016, btw

If you have PO history enabled and set to retain deleted PO's then it will still have it in the history file. Also, what was on the PO will always be retained in receipt history.