It is definitely odd that the CPOW available short figure was cut in half in a day, especially because the short volume was way lower yesterday:
20110303|CPOW|82109|0|496599|O
Per the new Regs, I believe, if I am understanding them correctly, there are 13 days from a short to cover or it's a failure to deliver. But someone with a better understanding of the regs could pipe in.