You are paid for your time on stage; you are not paid to practice, you are not paid to load / unload. If the amount you are earning is not worth it, then get off stage.
This is how every job works.
There was an engineer who had an exceptional gift for fixing all things mechanical. After serving his company loyally for over 30 years, he happily retired. Many years later the company contacted him regarding a seemingly impossible problem they were having with one of their multimillion dollar machines. They had tried everything and everyone else to get the machine to work but to no avail. In desperation, they called on the retired engineer who had solved so many of their problems in the past. The engineer reluctantly took the challenge. He spent a day studying the huge machine. At the end of the day, he marked a small "x" in chalk on a particular component of the machine and stated, "This is where your problem is." The part was replaced and the machine worked perfectly again. The company received a bill for $50,000 from the engineer for his service. They demanded an itemized accounting of his charges. The engineer responded briefly: "One chalk mark $1. Knowing where to put it $49,999"
Moral of the story... Itemize things however you see fit. They can only screw you out of your talent if you let them.