I agree. I don't know what's going on but during the Yankees game last night, it just stopped updating at all. It's doing it again now for the Mets-Marlins game.
ScoreCenter XL was only 2-3 seconds behind the TV. MLB, if it updated at all, was 30 seconds or more behind.
The app description says realtime updates. I think the "frequency" setting is for the scores up top.
I'm really hoping this gets fixed. At-Bat has a really nice interface with tons of info. I'd love to use it...especially considering I paid $14.99 for it.
Oh and no push notifications? Lame. The iPhone app has them and so does ScoreCenter for the iPad!