Yes, EXACTLY why the gen is turned off. And, speaking of power checks, that PITA three minute wait during a Arriel ground power check is also a function of the engine being N1 rated.
The same guru engineer discovered that the predicted performance would be too optimistic if you didn't let the engine "cook up" during the gnd pwr check. The N1 & T5 numbers after three minutes are representative of the engine's condition in flight. But, I don't understand the dynamics of the cause. Something to do with the turbine blades growing and closing (or opening?) gaps... ???
Sorry, don't know about the max fuel flow question.
HO5S