It could have something to do with this line from the press release attached to the MovieStock on 28 Apr.
"Warner Bros. and IMAX also plan to release an additional 15 films over the course of 2011, 2012 and 2013, including Gravity, Dark Shadows, Fury Road, Batman 3, and Superman."
2011-2013 is a long time for a movie stock to mature, especially when one considers the near future of a very H$ hungry stock like any of the summer 2010 blockbusters. My guess is temporary redistribution of funds... lord knows that's what I would do.
2Cents