No worries. Leave it be. As long as you don't have to crank the pressure up to 15+ (and therefore overcarb your beer) to dispense, then you are fine. If you notice that it is hard to get any head on it at all - then you've gone too far - trim some. If you ever brew a wit or a very efforvescent Belgian - you might need to go even longer.
You acually measure from the middle of the keg - because that will be the average height differential.
Mylo
