Those that have read the EASA paperwork will no doubt have picked up on the fact that it mentioned that the failure was not necessarily due to either the amount of torque applied or the number of hours accumulated...
...therefore why does the L2 have 4 1/2 hrs compared to the 3 hrs for the 225 with the 5101 shaft?
Is it reasonable to assume that the overall load through the 225 gearbox and different harmonics (5 blade head etc) produce a different type of fatigue/vibration pattern and therefore a greater chance of failure?