Prozack,
Good question. If I had to wager a guess at this, I would say that a team is usually more intensely focused when they're on the road, especially an SEC team where every weekend is almost like a bowl game atmosphere when they play away. The team realizes it is going to be that much more difficult to win. At home, teams tend to rely a little much on home field advantage and hoping that the crowd element can take a toll on the opposing offense. Not to mention the fact that home teams always feel more comfortable at home. The moment a team gets comfortable, they let their guards down.
That's the only reasonable logic I can think of. Otherwise, I'd say it's just crappy luck.