I just did Psych this year and had my exam yesterday. Your SACs will scale according to your cohort (your school year level) but, there is technically a way around it where you, yourself can pull all A+'s for your GA's and that's purely from top exam performance if you believe that you'll do well but not well enough for 40+ then relying on your cohort to scale might work but if you individually can top the entire state then it doesn't really matter on if your SACs scale or not.
Example from 2022: the A+ mark was 95/120 marks on the exam. Now if you had scored 110/120, it is very likely you could achieve a 47-48. But idk VCAA is weird and they scale SACs very strangely. But most importantly rely on your own performance