Graham,
I've been playing thru amps/speakers for 40+ years, and it was just recently, that I learned the importantce of what you stated.
(I think that I will ask Nigel to change my name to "The Student")

Also, a friend of mine uses a 1000 watt Peavey digital amp, going into 1 Bose 802. He is doing this multiple times, weekly. It sounds fantastic, super clean, crisp hi-quality sound.
I told him, granted you are driving 8 or so drivers in that 1 Bose, but still, 1000 watts...its going to blow some night.
He says no and stated what Graham noted.

Although, for the record, he uses 2 of the 802 speaker cabs when he is playing the large 800+ annual things he's involved with.
But that would be logical to carry over the larger area with the amp working continuously at that high output.