Yes. You should have done this. I did it this holidays and it frees up a lot of time. Further just takes time. That's it. For modules, I would definitely recommend:
1 -Number patterns
2 - Graphs
3 - Matrices.
1- because they can only test you on application of formula. However, some independent companies go too far with this on some exams i've done (INSIGHT for example), but on all the VCAA's they have been a joke.
2 - This is personal really, mainly because I did methods last year. Still, since you are doing it as well, this part of the course is just straight lines and some inequalities.
3 - matrices - because further only goes as so far as transition matrices, again, which you do in methods.
Normally, I would also recommend geometry but it is a horrible, horrible module to make mistakes in. Same with business. Decision maths makes you think. This is not what you want to be doing in futher.