If you bring your car into a shop, they hook up all the rest equipment for a complaint and find that everything is working according to specs after the technician spent one hour going over everything, should that be free? How will that technician get paid? Should he just donate his time because everything is operating properly. The Service people should have explained that to you when they wrote it up. Everyplace I have worked at has a diagnostic fee that is charged whether they find something or not, pretty standard.
2015 Chev Silverado 3500 dually D/A
2016 Cedar Creek 36CK
B&W Patriot 18K, Trail-Aire pinbox,
Level up, dual panes & all that stuff...