So when items are back order or they have to be remade we can print the packing slip and adjust the qty that was included so we know exactly what is still left to be fulfilled. (And it would be amazing if it would give us the option to send it back to purchasing and then production).

But that way if only 5 of 10 shirts were included because of a misprint it's noted on the on the packing slip like in Purchase Orders it can be partially filled.