open up the servo and look at the pot, don't recommend it if you haven't done it before you'll probably ruin ther servo. there you will find your differance. basically a higher grade pot means better centering and position sensing, also becuase of the cleaner resistance on the pot the gain on the amp is turned up a hair meaning it has a bigger ear to listen and make position changes. but go ahead and trust those specs
you'll probably never notice the differance since it's minute but is there