Well looking at your sig it looks like u want adv maths and commerce.
Commerce has an excessive demand, and it will most likely increase next year, i'm guessing that it will increase by 0.5. ADV maths on the other hand, doesn't have as much demand. However since you're going for both, expect it to go up about 0.5~1.
There's also some courses which have an artificially inflated cut off to make it look more prestige, this typically happens in courses like engo, comp sci + adv comp sci, and science at USYD or UNSW. I seen plenty of people get into engo with 5~7 atar below (and no it's not bonus points which made up for these missing points).
Commerce is not artificially inflated, there's actually that many demand for it.