I believe you can do A lot better repeating a subject. Although VCE is generally understood, to be done by practice etc....some subjects are done well a particular way, to achieve the best possible score. Eg. English language Vs English Vs Literature
They are all English, yet too " ACE " them, you have to plan your way differently...and to understand that formula for success in certain subjects it takes time... Yet if you repeat a subject, you are much more confident and know your personal weakness' to which you can adhere a path the success.
In my view, and from people I have seen, and heard off, DEFINETLY you do MUCH better!