I think you'll find that the reason for the AAM week 5 is because there is no medical confirmation required and also no counsellor supervision. While it will be fine for most people, it could be dangerous for some people not do the AAM week 5.
I would never recommend that anyone skips the AAM week 5, but if you do just be sensible about it. If there are any signs of a problem or something doesn't feel right, then do something about it rather than ignore it. Don't assume that just because it is fine for other people that it's also fine for you too. We all want to lose weight as fast as possible, but doing it safely is the most important thing.
Having done a VLCD before, I know it is relatively safe for me to now do Exante. Even so, I've been thinking about doing 8 weeks and then an AAM week, rather than go for the full 12 weeks. But I'll see how things go.