estimate charges on 1995 GMC Safari

What is the standard way of charging for an estimate? By the Hour? Flat Rate?

Asked by for the 1995 GMC Safari
99.9% use flat rate. Just becaise a tech can do the job in 1 hour and the flat rate calls for 2 doesn't you should only pay 1. If you find a shop that charges by the hour, most assurdly you will pay more than flat rate. Understand something the labor guide is exactly that. A GUIDE, NOT THE LAW! Some labor guides are way off either way (high or low).