yeah, in my case i went from a 24 (p-7, v-8, b-9) in april 2002 to a 33 (p-10, v-13, b-10) in april 2003. the jump in my verbal score is particularly ridiculous (8 to 13), as it's generally not considered something you can study for and i didn't exactly go on a mad reading binge for one year. i'm surprised i wasn't investigated for that drastic of a jump (i've heard of that happening).
the main difference was that i just wasn't mentally prepared when i went in the first time (no sleep and just a really bad couple of months before the test). took a prep course the first time, and studied on my own the second time. didn't really study excessively the second time around, just had a few more classes under my belt (biochem, orgo lab) and focused on my weak points.