So Choppy - you overload the aircraft and manage to stagger to the hover (at the very top of the green arcs as you love to insist) - what spare performance have you got to transition?
You may have a 5 min takeoff rating but you are extremely likely to be eating in to that just hovering.
Suppose you do stagger into forward flight and need to climb - have you accounted for your large decrease in climb performance, your reduced VNE (which graph are you going to use for that since you are above MTOM?)
If you have an engine failure, have you thought about how the remianing donkey is going to cope with that excess weight?
If you don't think that just hovering at above MTOM is stressing the aircraft - high torque/T4,more TR thrust and strain on the transmission - then you aren't an engineer.
Your assertion that there is no difference between MTOM and above MTOM ignores the fact that you are very unlikely to be able to do this 'in the green arcs'.