Yep, that's the idea. However, rank 2 and 3 might get a lower or higher moderated SAC mark. Also note that when stating exam percentages, we're really only interested in the weighted percentage and not the raw % itself. That's because getting, say, 60/120 in an exam could put you in the 90%ile of students if the exam was extremely difficult.
Moderation is a bit of an 'iffy' issue from past experience (statements of marks). Below is a largely true story with grades just modified for the sake of preserving identity.
A student (let's call him Bob) did very badly for his exam and got a C for his exam. He was rank 5 in a high ranking cohort for German which should've meant that he gets an A/A+ from his SAC performance. He performed equivalent to the guys that were rank 30-ish.
What happened, though, was that the other students picked up the slack so his rank 5 SAC score scaled to 50/50 for both Units 3 and 4, and his SAC scores should've been moderated, but didn't happen.
His exam score was a meagre 270/400 in comparison.
Ended up with a high 30s study score even though the exam was equivalent to a very low 30s score.
Technically speaking, moderation should occur, but if not many students perform badly they probably won't.