Upload & Sell: Off
I don't believe doing this adjustment would guarantee a future lens from being off, tolerances still could combine destructively... personally, if it works why fix it?
Well, as i've said, all my current lenses are in the (-12 to -15) range. So that means that the camera it-self is off by (roughly) -15 out of -20 possible, which only leaves 5 units of possible adjustment in the "-" range... So if I ever will get a lens that will require more - i'm fu@#ed!!! As such, it seems like a good idea to get the camera body calibrated to zero.