The entire idea seemed to be giving students who were bored by the material more work than other students so they could be even more bored by the material but while never going at a faster pace because that would result in students learning material that wouldn't show up on that years standardised tests. Tracking was the norm, but at least my school was extremely reluctant to either let people skip a grade or hold back people a grade so they were preparing for standardised tests that provided them a reasonable challenge, as that would mean you were doing school with people who weren't your same age peers and that's bad!
I just never really understood why these tracked math programs were a good idea? They seemed EXTREMELY stupid to me at the time and I just don't understand how these classes were ever supposed to be a good idea. In the non-tracked classes you could at least blow through the work you were assigned more quickly.