On the item fulfillment form we have set up our system so a packer can verify the qty of the items they are packing into the box before pressing the "fulfill" button and printing the packing slip. 

What would be really great is if the qty. fields on the screen(form) were blank. Such that a picker would pick the items according to the amount listed on there picking slip, then handed the order to the packer and the packer called up the order.  The packer is then required to enter the correct(and only the correct number) into the field on the screen.  If they, the packer enter 3 instead of 2 which is what the order called for it would tell them they were wrong on that line item.