Lol don't worry about it. My school attempted to scare students as well by telling us that a couple of years back, 2 students doing the same subject both scored 'As' for GA1, GA2 and GA3 and yet one received an SS of 40 whereas the other was handed a 33. They said this came down to the students' individual GAT scores.
However, this is inherently misleading because there's a difference between a low A and a high A. Plus, it'd be pretty unfair if your SAC scores were scaled down merely because of the people in your cohort - SAC scaling is largely governed by cohort exam performance and your ranking and not the GAT - perhaps the latter may have some influence, but I'm pretty sure it really only comes into play if you require a Derived Examination Score or something.
Check previous threads on this forum about the GAT and you'll get the picture (it's treated as a joke).