Hi, I am not a shop owner, but I have had parts machined for me before.

At least the shops I worked with, there were different prices for a wide variety of aspects:
- Each machine center / group of machines were priced differently per hour
- How busy the shop was
- turn around time needed
- Finish (surface, not anodized vs not) was as important as tolerances
- If they wanted the job (regardless of busy or not)
- If they had the material in stock or not

I am actually glad I don't have to quote these complicated aspects. My quotes are just for my own time, and that is hard enough.