The person testing you on the CFA, is "SUPPOSE" to know the CFA. There are only a couple things you can max on. E.g. Pullups/situps/pushups. The person testing you will tell you if you maxed those 3 tests. You can't go over. "Unless your tester doesn't know what they're doing, and aren't familiar with the CFA". In which case, you shouldn't have them testing you until the understand the test. As for the other tests, unless you've got a clock built into your brain, or a tape measure built into your eyes, there's no way to STOP at the max.
Definitely make sure that your tester is familiar with the test. I HAVE SEEN an applicant have their CFA scores questioned, because it's obvious that the tester didn't understand the test. On individual had a shuttle run in the 4 second area. Obviously, the tester didn't realize that it was "2 Laps". There's also been some testers who didn't perform the test in the right order, with the right rest period. I.e. Did the mile run first, which made it more difficult for the candidate to then do some of the other tests. Or having them do all tests immediately back to back without a test, and thus also impairing the candidate's true capability. Anyway; if the tester understands the rules, there's no way to go beyond the max in the 3 areas.