Except that is really the same issue, which I thought was obvious, and is why I ignored it.
Taking a ST in conjunction with the AP course make the ST relatively ‘easy’. “Uuuuuggggeeeee” unfair advantage to kids in top high schools and prep schools, who can offer AP’s in Soph and Jr year.
Heck, even Math 2 depends on the HS curriculum. Our HS, for whatever reason, holds out one section of precalc trig for the opening sequence of Calc BC. When my son took M2 in spring of his Jr year, he said there were a couple of questions on which he had absolutely no idea, since he had not seen the concepts before. But come September, those concepts were covered in the first week. Voila, aced the retake of M2 in Senior October. Yes, it was in time for college apps, but to get to BC by a senior, one has to be tracking from middle school. (And yes, our HS could esily move that math segment to Junior year; haven’t the faintest idea why they don’t.)
But the fact is that a typical College Prep course will not cut it for the ST’s anymore, at least for those desiring a score that starts with a 7 or 8.
That’s the beauty of the SAT. It only covers math up to Alg II, and only a handful of questions on Alg II. So it does not disadvantage kids in ‘regular’ urban high schools.
(ACT Math includes trig, btw, so a strong score requires knowledge of trig.)