Steve, Dread's the "go to man" on these issues, but my understanding is that the dreaded (heh, heh) 12th fret hump can be caused by humidity problems. I began having a similar problem with my D10S about a month ago. Two weeks in a hard shell case with a humidifier took care of the problem. I did have to adjust the truss rod after the guitar re-humidified, but no biggie there.
There are a lot of little humidifiers commercially available. I use a home made one that Pike suggested on that "other" forum:
It's just a soap box, with holes drilled in the top, and a damp sponge inside. I would probably give that a shot before looking at adjusting the action.
Guitars and other stringed instruments: Washburn D10S, Washburn EA52SWCE, Washburn Cumberland J28SDL, Washburn D46S12, D'Aquisto Centura, Rover RM-50B Mando
Amps and Cabs: Behringer AT108, Firefly Tube Amph, Blackheart Little Giant BH5H, Shiner's Custom Cab v.1.0
". . . because without beer, things do not seem to go as well . . ." Brother Epp, Capuchin Monastery, Munjor, Kansas 1902