This is hypothetical but based on fact! If I'm ranked 2 in a cohort of 40 [psych] where we have sac marks of 97 and 96 respectively. In exam say I get 92 but rank 1 student gets only 84, (and assuming no one else in the cohort will even get close) does my SAC get moderated down to 84?
I just saw this question and the reply "Yes probably" needs commenting on.
The rule-of-thumb formula is your post-exam SAC = your pre-exam SAC x (cohort's exam average / cohort's pre-exam SAC average)
Described in words your SAC is moderated to reflect the whole cohort's exam performance.
Only in a rare case where everyone in your cohort (except you) drops 13 marks like rank #1, then your SAC gets moderated down by a similar amount to around 84.
If rank #1's big drop is only him/her and the rest all drop 4 marks like your 96 to 92, your SAC would only drop ~5 marks to around 91. IOW it depends on the whole cohort (thus cohort's exam average) not just one person.