I'm a big fan of King Schools. Always entertaining and informative. I did their Helicopter FIRC before I was a helicopter CFI and I found it very informative. They give a discount to NAFI members too.
I have done fixed price flight reviews in the past. This didn't include the aircraft. I would not have an issue with fixed price on instruction for a rating either.
If you guarantee the price for everything and then student only flies occasionally it would be unfair to the school that you...
Interesting to think there is a Cessna way of doing things when it isn't in the manual. In other words, someone at Cessna decreed that this was the official way when it was really just their way.
The correlator on our 280FX seems pretty good and I find myself adjusting the throttle very little. With that said, when you do make changes you have to be very gentle. Also, just got TT straps and it's like a new machine.