Well this is all well and good, but the way that this year's HSC marks will be scaled will vary from the way that last year's HSC marks were scaled. A few things to keep in mind.
1. A quick glance at the table shows me that unless you got 100% in 2 unit Maths, every mark got scaled down in that as well, not just General Maths.
2. Last year's HSC paper was quite straightforward. A good indicator of this is the proportion of the candidature that were given a Band 6 result. Usually this is between 2.5% and 4%. Last year this was around 5.5%, so quite high. In other words, a more difficult paper this year and you'll probably find that marks are not scaled by so much.
MOST IMPORTANTLY
3. Don't stress about what is outside your control. The bottom line is that you have to do the very best that you can do, starting next week. That's it. Everything else is out of your control and you can't do anything about it.