There was speculation early on that they might do this to make things more "fair" for offsite guests and AP holders, but there is no evidence at all that this is true. Often additional FPs are released if park hours are extended, which often happens around 30-days, but do not waste your time getting up at midnight 30 days out.
However, do keep checking, as FPs open up all the time as people rearrange plans. And you can watch this site for availability as well:
http://www.thedibb.co.uk/forums/showthread.php?t=835236