I was trying to comment on someone who said they charge by the hour. My point was that if you're hitting a job for 4 hours to get a DD Toyota to 80%-90% good enough and a Ferrari for 16 hours to get it to 99% or whatever, I don't think that those hours are interchangeable. The rate should be higher for the Ferrari, the attention to detail, level of skill required, toolset required are different.
Maybe it makes sense to charge the same for a wash on a Camry vs a Ferrari, but you have one oops on the ferrari and you're going to have to wash the Camry 50+ times to pay for it.
Hey, you're the guys doing this for money, its your world, do what you want. I'm just offering my outsiders opinion.
To further demonstrate, if you weren't a 1 man show, and you had 2 guys working for you, 1 with like 1-2 years of experience and was OK, and the other with 15 years experience and was top of his game doing paint correction, you'd be paying them different. You'd have the 1-2 year guy turning out shiny DDs and billing at a lower hourly rate with the 15 year guy doing high end corrections, at a much higher hourly rate.