Oh, I didn't realize that it had so little movement, I'm sure they take a few more than 10, but still... My comments were based on the observation that a lot of people at second look had acceptances at other top 5-10 schools and was assuming that a decent portion would take other acceptances.
On the other hand, I do remember someone mentioning that Duke has a pretty complex algorithm for calculating how many acceptances they send out per year, taking into account everything from the number of apps they recieve to their US News ranking to how far the basketball team makes it in the NCAAs...