It doesn't really matter what you get internally, per se, but rather your rank.
If you are ranked first, then it is you who determines your destiny. What I mean is that your exam mark in the HSC will be equal to your assessment mark. If you are ranked lower then you are somewhat at the mercy of your peers.
Furthermore, the difficulty of the papers and marking is very different from school to school.
To acquire a modern history mark of 96, you would, I believe, have to achieve a raw of perhaps 90-95 in the HSC. This will be your exam mark. If you are ranked first, the 96 will also be your assessment mark, and you will end up with 96/100. That's how it works.