Well, remember that the English Extension 2 course asks that you build on what you've learnt in the base courses. - they want to see that students are able to manipulate style, content and concept as well as experiment and open new boudaries. Working within convention, they can't see that you're any good at tectual manipulation - you may as well just be imitating another writer.
That's why the YWS pieces are "out there" - because really, that's the aim of the thing: to create new ideas, new meanings. I mean, you can't expect someone taking Visual Arts who paints a series of very pretty pictures of flowers to earn fantastic marks, eh?