There are actually a decent number of candidates who max the CFA, according to the USNA officer we talked to. Maybe 20% or so, which surprised me. I really do get the impression it is an overall assessment, and if a candidate is very strong in other areas the CFA is less significant, but if it is a close call the more fit kid may get the nod.
My son was seeking a perfect score towards the end on the summer, but started soccer before doing the CFA and got an injury which made most excecises almost impossible until recently. He will now do the test within a week, but won't get the score he would have if he did it in August. He is a very fit muscular kid, and was able to do a fantastic ROTC fitness test a couple weeks ago, including a 5:29 mile which we didn't think was possible, but the CFA is so different. Hoping for the best though.
I think a point or two on the ACT is worth more than a great CFA, but its all very relevant. I get the impression that all of the academies love to bring in super strong fit kids who they don't need to wory about physically. And most candidates fall in to the category where they are competitive in the admissions analysis, rather that automatic. Thus, CFA score may be the difference between getting in and not.