[mGGDrGooSe]

I believe the original reason behind the week long lock out was to encourage people to play heaps without worrying about how it will effect their ladder rank. So to encourage a last spurt from people who suffer from rank syndrome - which is probably most of us at some stage.
Also, I never got anywhere near those points before being promoted. I'm pretty sure the MMR must be based on things like APM and graphs (mining rates, army value rates, etc.) as well. Cos I floundered in silver NA for a while and then got promoted after about 5 straight wins after taking a break.