Fretboard has to be removed and reinstalled, Truss rod is $50, Graphite rods are $44, routes for the two graphite rods, Labor is $100.. so just shy of $200. The truss rod that he's using is a pretty nice replacement, higher quality than the original, so I think it's a little expensive.
I guess I'm used to a bass where the truss rods can be slid in and out like no big deal.
Makes sense to upgrade with the increased tension, though.