"How did the usage of the aircraft (MAUM, high cruise speeds etc) differ from the military flight regimes"
I'm pretty sure that in a "hot war" the helicopters take a real beating (and we do see failures then but they are thought to be acceptable or at least likely to a degree
Offshore is day in day out, several times a day for years - to some extent the difference in use between a fire engine/truck and a bus..................