I can remember the period in the mid eighties when the logging if flight hours changed . Up to that point flying time for both crew and machine was logged from moving for the purpose of take off to shutting down the rotors. It was then changed to the crew logging it as before but only actual flight time being recorded for the aircraft. Concern was raised that all the running time, which could be quite extended in certain circumstances, was ignored despite concerns that there was a fair amount of stress and wear going on.
These objections were overridden for the obvious financial reasons.
On the fixed wing side engine running time is on the clock and various stages of power are recorded. The wings don't do a lot on the ground so taxiing and suchlike can be ignored. Are we right using the same criteria for helicopters?