At my advanced age I like anything they will let me ogle it from a far and does not call the cops
Why are you doing so many PTs? Are you studying at all? You probably could get better use of your time by spending that hour each day just going over practice problems, past tests, etc. You're still missing questions, so why not aim to get them all right? As for an indicator of your score, I agree that you have to take a full PT to get a good idea of your score. After that, I'd say lay off the PT's until Dec. Keep studying, but there's no use repeatedly taking PT's and repeatedly getting questions wrong. Your goal should be to study, occassionally take the PT's, and see a rise in your PT score.