U could find out urself by looking at the study design and with some real simple math:
Unit 3 only has 2 AOS, each worth 50% of the unit grade, which is worth 16% of ur total study score.
So, each SAC is worth 4 marks out of ur 50 study score. A 93 in the first gives u 3.72 and a 76 in the second gives u 3.04. So out of a potential SS of 8 in unit three, u have 6.76 SS points. Now i dont think the exam has a MASSIVE impact, it really depends on how ur entire cohort goes on the exam so VCAA knows how hard/easy ur sacs were and moderates them, but i dont think it is like too extreme, but it does have a big impact. For arguments sake, lets say ur cohort scores the exact same average on exam as sac and all ranking stay the same. Then we will find ur unit 4 average.
U don't have any results for it yet, but unit 4 is MORE important than unit 3, it makes up 24% of ur SS, or 12 points. Assuming u get the same scores as unit 3 (they will prob go up as u have more experience/familiarity with the subject tho there is more to learn in unit 4), it would contribute 10.14 SS points. Then the exam, which contributes 60% or 30 points. Getting ur unit 3 average as THE average for ur exam and assuming ur sacs don't moderate, ur final SS RAW would be 42.25, which scales to basically the same.
So yeah, thats pretty good but DO NOT take that as a good indicator. Alot of things were assumed like ur sacs don't scale, and u maintain the same average doing unit 4 of bio and u get the same exam score and ur GAT results r also not like extremely, way off and bio doesn't suddenly scale this year and stuff. But yeah, its a good start, just keep it up!