I liked the setup at one shop I worked for, with the average bike we told them the tune was 70.00 and we had a 25.00 parts possibility (had a better term I can't remember). Basically if we found something that needed replacing and it cost 25.00 or less we just did it so it was ready to go and we didn't have to wait for approval. 25 could cover front and back pads, a replacement chain, a worn chain ring or several new cables. Just meant we didn't have to fine inspect every inch and expect to get it right till the bike was in the stand. Parts over 25 was a call and wait for approval. More expensive bikes we put a lot more attention into the drop off but they still had the 25.00 which still might cover cables or housing or a bb. Owner wasn't big on abusing the system and customers were happy to not have to field calls. Worked well.