You are still ignoring the fact that the lower number of high performance engines still use the majority of aircraft fuels and provide most of the revenue to commercial operators. Asking them to derate their engines so that you can run a lower octane fuel (in spite of the fact that your engines will run on their high octane fuel) is like asking you to stop driving your gasoline powered car to give more room for diesel trucks on the road. Derating high performance engines would be incredibly expensive and could actually render the aircraft unfit for its original purpose. The FAA’s pronouncement of approving engines to use 91UL is creating another can of worms - mainly because it gets back into the argument of whether an FBO should have two separate pumps for Avgas, in addition to many that also dispense Jet A. We have enough problems with misfueling incidents between 100LL and Jet A. Dispensing two grades of Avgas creates another misfueling potential and exposes the FBO to the expense of operating the two grades along with the liability for fueling with the wrong grade.