i gave up years ago trying to figure the right way to do it. i decided it's your car, your paint/parts. i get paid on fridays just like anyone else. i do a weekly billing on time plus any materials or supplies bought.
bottom line is your about to make a huge investment in your car. if you dont do your homework and make sure of what your dealing with it's your fault. i dont go into anything blind. if i cant check references i'll pass. pay attention guys. it's a lot of money and the most important thing of your car.