Question about a Marvel comic book

I was looking on the Marvel website at the release calendar. I noticed that for Avengers A.I. # 2 it said print issue in store Aug. 7, 2013. But at the bottom it said, FOC Date Jul. 24, 2013. My question is, what the heck does FOC mean, and why is there a difference between that and the print issue?

http://en.wikipedia.org/wiki/Cover_date

As far as I know, it stands for Final Order Cut-Off, but I'm not totally sure what that means.

I don't think it's a different version of the comic though. Maybe it's like the last date that a shop can order copies in or something.

https://www.newsarama.com/2675-what-the-foc-how-final-order-cut-off-affects-the-biz.html