that $160 tool becomes quite handy and a rider will really appreciate King quality when he completely pulls apart a King hub.
had a guy come into the shop to get his King overhauled. the helical spines on his driveshell were worn to the point that they needed replacement. $50 part + 30mins of labor got him a hub that runs as good as new. for a rear King overhaul, we charge $30, which, honestly, i think is a mistake, as it's not what i consider to be an overhaul. more of a flush.
also, after seeing what i have, i don't really think that "overhauling" simply using 2 5mm hexes and flushing the bearings is adequate. the Ring Drive really needs to get cleaned thoroughly, and the tool is needed to get the Ring Drive mechanism out. also, you don't have access to the drive shell bearing without the tool.