$500 isn't too bad, there's a lot of labor involved and the motor must be pulled from the bike.
You might be able to just loosen up all the case bolts and pry the cases apart slightly to remove the seal, it's only being held in there by about a 1/4in on both sides of the cases.
If you must remove the lower case, maybe think about having the trans gears undercut and have the gearshift stuff freshened up (springs, cam, etc.) while you're in there. Way cheaper while it's already apart for the rod seal then doing it later on.:hmmm:
good luck.