The POS system option Display_a_Menu_on_Service_Scan controls the behavior at POS when a service job envelope is scanned.
If this option is set to False, scanning a service job will add the job to the sale as a pick up if available (i.e. job marked complete) otherwise it will add the job to the sale for payment.
If this option is set to True, scanning a service job will bring up the Scanned Service Action menu: