The text on p. 32 states the opposite: "the manufacturer’s rated minimum sine wave continuous average power output, in watts, per channel (if the equipment is designed to amplify two or more channels simultaneously) at an impedance of 8 ohms, or, if the amplifier is not designed for an 8-ohm impedance, at the impedance for which the amplifier is primarily designed, measured with all associated channels fully driven to rated per channel power." Subsequent to that, they only exempt HTIB systems from the "all associated channels" rule for the aforementioned "different portions of the audio frequency spectrum."

FTC regulations require that the specifications provided to consumers conform to this. How manufacturers word it (i.e., with or without the word "simultaneously") is irrelevant, because the FTC requires the underlying testing to be the same either way. This prevents companies from doing what you suggest - comparing "apples to oranges" in their power output claims.