That's not true, unless the the no.1 ranked in sac scores achieves a high score in the exams (which isn't always the case). Sac scores get moderated by your exam ranking. Let's say you're ranked 5th in sacs in your cohort, but rank 1 in exams, essentially you're sac marks are replaced with the no1. ranked in sacs marks.
Nah you've got it the wrong way around.
SACs vary depending on what school you go to. The actual SAC marks are of absolutely no consequences - they are never involved in scaling.
Scaling involves rank and exam scores.
If you are rank 5, and then do the best in the exam, then it makes sense that you've just crammed really hard for the exam right? So part of your study score is just your exam mark (GA3) to recognise that you did manage to successfully cram.
The other part is based on your rank - otherwise the SACs would essentially be of no consequence, you could just bum around all year and then cram for the exam.
You are rank 5, so VCAA then gives you (approximately) the marks of the 5th best exam.
So say the exam scores are:
1 - 95%
2 - 93%
3 - 89%
4 - 86%
5 - 85%
6 - 82%
7 - 80%
8 - 72%
9 - 70%
10 - 66%
These exam scores are essentially subbed in for your raw SAC marks. So it doesn't matter who got them on the exam (you get your own score for GA3 but that's separate). So ranks 1-10 would get these exam scores in order from 1 -10. So the person who was rank 1 may have only been averaging 80% in SACs, but if your cohort got these exam scores that would mean that your SACs were harder than VCAA standards - which is why raw SAC marks are of no consequence. This is also why you should help everyone in your cohort revise and do well on the exam - ultimately it may end up helping you.
@lear beat me to it, but I'll post it anyway