Yeah, that last part about restricted movement would probably irritate the heck out of me as an operator of my own business, really enjoyed the freedom to choose when and where I wanted to relocate.
That's also a great way to look at it (the 20% covering fuel). It probably should have been obvious to look at it that way. For the most part yes, it was only when the carrier would strand me w/o a load for days on end that the fuel costs of just sitting would make money tight.