I hate to say it but he is a lazy drywaller. When I did my shop the drywaller
just dropped the end he needed to put the drywall up and put the opener right back up. My shop has 12' ceilings too.
It is most likely that your plumbed directly off the pump. The pressure tank
is your source of constant pressure in the system. As the pump cycles on and off the bladder in the pressure tank is what gives it the uniform pressure and not the pump.