you need to check out this site-I am not saying Scot is wrong but I don't think AB packs are thinner. I am pretty sure they are the same size as other 206 packs.The AB cards are thinner or at least 98% of them are or at least the 80 or so ABs I own are that way.
I don't think we have found the exact reason the AB cards are cut different than other 206 cards.
I am always looking for answers and trying to learn
http://www.baseballandtobacco.com/