didn't read all of the posts but the issue with power ratings is they don't tell you time of the test, the test conditions, if the amp works after the test, etc.
i'm sure Boss measures their published numbers using 16V supplies, square wave signals, and at the point of amplifier failure.
for me, a useful system of amplifier power measurement would be something like this
12VDC supply, 20Hz-20kHz pink noise input signal (of
#V RMS input, with gain/input sensitivity set to
#V ) into a 4 ohm load for 1 hour with
(i.e. amp works after test and meets all specs after test)
any power "rating" other than that is near meaningless to me.