HS kids, sigh. Gifted son got A’s senior year in AP calculus, B’s in AP statistics because one counted homework (zeroes on homework plus 100%s on tests yielded a first quarter B). The B’s he got in AP US history the year before were deserved- his teacher was spot on about his essays (eg he needed to focus on less scope so he could finish his thoughts) and he could have improved but got the 4 on the AP exam. Final semester senior year the chemistry AP exam was in the beginning of May and school ended in June- he got a C in AP chemistry and a 5 on the AP exam (he told me he didn’t like the teaching although he liked the teacher as a person). By then it didn’t matter for college admissions. In his case he needed to go to college (was 16) to have classes worth his effort.
It can happen that a student does not need to study or do the work for a HS class because s/he already knows the material. However, good study skills are needed for college- top schools will cover a lot more than the AP versions. Junior year (and before) courses will have AP scores available in time for college applications. There is a reason schools look at unweighted gpas, test scores, essays and recommendations and not use just one.
btw, I believe there is a good reason to not do class rankings. The kid who takes a full load of the most rigorous classes available and gets one lesser grade falls below an okay student who takes study halls and easier classes.