Well, my friend spent a lot (understatement, more like doing all-nighters and coffee binges) of time spicing up her portfolio and ended up with just 36 - 37 raw (can't remember exactly) ... which scaled down to 29 or there abouts. Apparently the teacher didn't like the "style" she "structured" the folio/dresses on - even though it seemed pretty damn awesome to me. The upside was that my friend did D&T in year 11 so the score wasn't too hard to recover from.
I think it's better to take up if you want to do a creatively inclined course after VCE (ones that look at your folio), rather than doing it for the score. (Obviously if you have passion for it, do it). There's a lot of effort you need to put into the design subjects if you're not already "pro" - whatever the criteria for that is.