The power slider of the fuel cell does not affect the power figures in the performance analyzer.
I am aware that the power slider can be adjusted in flight, but there is confusion as to if the slider works if the power figure in the performance analyzer does not change.
A possible fix is to have a fixed max power figure and a variable current power figure in the performance analyzer.
The power slider should also have 19 steps, not 20, as 20 steps from 10 to 100 causes weird increments. 19 steps will ensure increments of 5%.