You should understand that a good SAC score doesn't mean much. The more important thing is your ranking in your cohort and the performance of the cohort. At a high-performance school such as MHS, the SACs are ridiculously hard because the cohort is very competitive, and the school need to be able to separate the 50'ers from the 45'ers (thus need very very difficult questions to separate the extremely brilliant from the brilliant).
Example scenario:
In a high performance school, half of students achieve 40+ (A+ in all three GAs). The SAC scores themselves don't mean much, but the ranking is important. Let's assume the SAC scores turn out to be a symmetrical distribution with an average un-moderated score of 60%. That means if you scored 60% or higher in a SAC (which, is quite a low score for many people), you will still be ranked above the middle of your cohort. Which then implies you are in the group of students who will achieve 40+, and that 60% un-moderated score will scale up to A+ from statistical moderation (assuming the cohort doesn't collectively do horribly on the exam).
If low raw SAC scores is the only thing holding you back, here's a few things to think about:
-How do you compare to the rest of the cohort? Where do you think you would rank?
-Compare yourself to the people who are ranked below you. What SS do you think they will get? (if it is a bit hard to predict, have a look at the performance of the cohort last year)
-Compare yourself to the people who are slightly above you, what SS do you think they will get?
-Your actual performance will be somewhere between these two numbers.
I re-emphasize, the raw SAC scores doesn't matter. It is your ranking that determines what your moderated SAC scores will be. If you are similarly ranked with other high-achieving students, then even if your raw SAC score is at a petty percentage, so long as the other high-achieving kids have similarly petty percentages everything will work out just the same.