I think 24, 25, and 27 are all good ACT scores. I worked with a student last year with a 28 ACT (not a URM) who got into UCB, so presumably, schools of a similar, but perhaps a little “lower”, caliber would be willing to consider students with a 25-27 ACT.
OP, you got me thinking about how many of the same schools my two boys applied to since I never really thought about it. MIT, Vanderbilt, UPenn, UT Dallas were the only crossovers. They had very different lists because of different levels of achievements (DS #1 was way more accomplished in STEM and overall, with better scores, awards, etc) and major of interest (DS #2 was interested in game design, animation, industrial design, and a few easier-to-get-into schools for engineering).
Perhaps the difference was that DS #2 still tested decently well, but not near as good as DS #1 except in the writing portion of the SAT (DS #1 had 2320 with 800M, 790CR, 730W; DS#2 had 2230 with 750M, 730CR, 750W). DS #2’s SAT IIs were much lower (730, 710, 610 vs. 800. 800. 730).
I definitely did not expect the same stellar results that DS #1 had (got into all colleges), but I have to say we were incredibly happy and surprised at all his acceptances (16 out of 23 with 4 waitlists), but the majority of his schools weren’t reaches. He applied to 8 high reaches, and got into one (Penn), very surprisingly.
But unlike your DS #2, my son has disabilities, and would have done much better at one of the safety schools like UTD or UAH rather than at Penn. Your son will rock it wherever he goes! And listen-he can always try to transfer into one of the schools that didn’t accept him this year. I know several students who transferred from their state flagship into schools like Columbia after a year.