Perhaps EHI 01 crew will comment on the SOPs but it's a fact that two turbines at high power are more efficient than three at medium power so I see no real issue with it.
Thirty years ago, when this aircraft concept was being discussed between the UK's military (to decide on the Air Staff Target), I understood that the Royal Navy demanded an aircraft that could continue to hover if an engine failed. Due to the limitations and relatively low capability of the available engines in those days, some lateral thinking saw that on an aircraft of this size, three engines was actually more practical than two.
Delays to the aircraft occurred because of the inherent complications of a three engined helicopter main gearbox; I recall reading an article some years ago that claimed only one company in the world was capable of machining the casings.