If the governor were off and the Nr was in excess of 104% and then it was turned on, the detection system would signal the gearmotor to simultaneously decrease throttle and increase collective reducing the rotor speed to the deadband range of 101% and 104%. Conversely it would do the opposite if the system were below 101% and the governor was turned on.
I do not know if there is a speed at which the governor would not respond.
------------------
The Cat