Canterbury - are you sure that is not just a way of your employer extending the servicing intervals on the aircraft by claiming it is not flying when it is rotors turning on the ground?
You may not be airborne but the engine is still having to turn the gearbox which is still dragging the blades around plus the TR drive and any other ancillaries.
The manufacturers will have calculated the fatigue spectrum of the aircraft and I am pretty sure they would agree that rotors turning on the ground is still fatiguing the aircraft. ISTR R22s have an hours run meter which relates to rotors turning time, not airborne time for exactly this reason.