I'm not reading that treatise, but you can join your friend. This is my last word on the subject:
1) The definition of wattage (from memory) was exactly what I just read as the definition of the International Society of Electrical Engineers. Good enough for me!
2) Manufacturers are fast and loose with their values. The day before when I was deciding on a hub motor, I asked one company about the difference(s) between their 500w & 1000w motors because everything seemed identical; answer, they were the same.
3) I've had no problem subjecting my 48V, 1000w motor to a 30 amp controller @ 52V; Discuss this subject until you're blue in the face; it's the way many describe their systems; or are you implying that I'm prevaricating?
Enough said about this stupid subject; since we have these semantics professors patrolling the forum, I'll try to post less if at all. Too bad; the place used to be inhabited by only a really nice, helpful, intelligent, group of individuals.