Personally, I think one should organise their Top 4 IF they feel that they need to.
I knew a few people in Year 12 who felt that they needed to allocate a subject for their 10% increment, while others put hard work into all five (or even six or seven) of their VCE Subjects.
For me personally, I reviewed myself halfway through the year, and thought that I needed to allocate one of my subjects to be "The 10% Subject"
This didn't necessarily mean "give up" in this subject, but rather allocate less study time towards it. I felt that by doing this, I had stronger Unit 4 SAC and exam marks, across all four of my subjects, and even in the subject I allocated to 10%.
I personally believe that all Year 12s, at some point during the year, whether it's the first day of classes, or even leading up to the exams, should review and ask themselves "Should I organise my Top 4, or try my absolute hardest in all five subjects, knowing that any of them could fall into the 10% increment category.