Equalizer syncronization

I have a 3G iPod, and I've never seemed to get the equalizer sync function to work. I have set an equalizer setting (one of the built-in ones in iTunes) to each and every song in my playlist. I've synced these songs to the iPod. I've set the iPod equalizer to "Flat." I play the song on my iPod. But when I listen to the song, and switch the equalizer on the iPod to what the song is supposed to be set at, I hear a distinct difference in the sound of the song--the sound improves, in such a way as you would expect from switching from "Flat" to "Rock." So, I conclude, that the equalizer syncing isn't working. Am I doing something wrong here? Help! It's a pain to keep switching eq settings between my music and my audiobooks on my iPod.

Grape iMac DV Mac OS X (10.3.9) iTunes 7