Do these retakes replace scores in your previous test or are they more of a super score method?
Nothing ever “replaces” a score - what you scored on a particular date is in you record.
It’s no different than taking the test for a second time. You just won’t have scores for the sections you don’t take. And no composite score for that date.
It does sound like ACT will calculate a superscore from the full and retake scores, but that’s an additional data point. Just saving an adcom from doing math, I guess.
I was very surprised to hear the ACT would allow section retakes. Some colleges and universities do not allow superscores for the ACT, so section retakes would appear to have little value. Also, for college that do allow superscores, I’m not sure they would allow superscoring with just one section. If they did, why not just take the ACT four times, one section at each sitting. Makes studying a lot easier, but defeats the purpose of the test.
It’s a curious move.