You mean this one:

"when measuring maximum per channel output of self-powered combination speaker systems that employ two or more amplifiers dedicated to different portions of the audio frequency spectrum, such as those incorporated into combination subwoofer-satellite speaker systems, only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power."

I don't see how you can derive your conclusion from this. What this refers to, "combination subwoofer-satellite speaker systems" and the simultaneous testing of ALL associated sat-only channels separately from sub-only channels, has nothing to do with standalone multichannel amps.

What you say it "clearly states" is neither stated or implied, and must be taken entirely out of its context to infer. If you wish to misinterpret what is made abundantly clear in the document, I don't see a need to discuss further.