It's not deceptive - there's no commitment or understanding that the only thing he's doing when out of sight is work on your car. (And they don't bill based on

It's not deceptive - there's no commitment or understanding that the only thing he's doing when out of sight is work on your car. (And they don't bill based on how long they're gone - they bill based on how long they actually work on the car, in theory.) On a computer, however, users generally assume that results are being delivered as fast as possible, even though in reality there's usually other things eating cycles.