Let me tell you that I have taught std English as well . I can also tell that three of my standard English students went straight to Sydney uni and are studying medicine. Depending on your subject choice the difference between stdevand adv is minimal. My experience is the majority of std English students who work to capacity are barely , if at all , impacted by doing standard as opposed to Advanced . There is a difference in scaling but my experience is that it basically has no impact on an ATAR if the standard English students works to capacity