The %Power read out is a model of the engine, and my not reflect actual engine power. There is also a step where you need to tell the EMS what engine you have.
Here you have a high fuel flow for that altitude, coupled with a high RPM. At 11K WOT I’m at 20.6” MP so your 20.8” sounds about right.
The result is you may be fooling the algorithm to show a little higher % PWR. Doing a quick look at screen shots, at 11000’ my SkyView is showing 63% power, and 68% at 9000’ (WOT, LOP).
Depending on your engine, you might want to try a leaner mixture at that altitude. This may be a problem with a carb, but worth a try. For my RV-8 I’d be around 8gph at that speed and altitude.
Carl