It really doesnt !
What the sell price (that bter posts) for 1 CRSALE will go up by 1% each day or what?
If not how you will figure out when I bought my CRSALEs?
They will just consider you bought with x% amount more than what you bought with. So, on day 1 if you buy with 1 BTC, they will consider that 1.3 BTC. Easy peasy.