09 FLHX rear shock air pressure

[Golfman]

In reading the small owners manual that came with the Bike it seemed to call for 20 lbs pressure in the rear shocks. Elsewhere, i read that the Maximum pressure for those shocks is, also, 20 lbs. - that seemed strange !! Got my Bike back from the dealer after the 1,000 mile checkup and there was over 30 lbs in there. I reset it to 22. Any opinions on how much pressure these shocks can take; and what is the proper setting???
Golfman (Dave)