when i was practicing a loooooooong time ago, i took the last kaplan practice the night before my dat and got a 24...ended up with an 18 on the real one. you should expect a 6-8 point drop from kaplan....just because the angle rankings and hole punch are considerably harder on the real one.
i felt barron's was a more accurate predictor on the type of questions, even though they did have some mistakes in the answer keys.