Henry, that Wiki article is reasonably well-written overall, but isn't quite precise or up-to-date on the legal requirements. The FTC concluded its most recent rule making on the amplifier power ratings almost a year ago and the findings are shown
here and became official upon publication in the Federal Register on 1/26/10.
That suggested CEA standard actually came out about 9 years ago, but wasn't very widely used because its one channel driven at full power procedure wasn't permissible for the basic rating under the FTC mandate(yes, that's the term, not "recommend"). As you see from the linked findings, the Commission specifically rejected the option of allowing the CEA standard to become the Rule and also rejected the "all channels driven" proposal.
The language in the existing regs was retained, but more specific guidance was provided in two areas in which there'd been some question: the rating had to be done with at least the left and right channels driven simultaneously at full rated power(for at least five continuous minutes), and the basic rating had to be on a per-channel basis, not an aggregate of all channels. This won't be likely examined again for quite a few years.
