I agree with Bruce, should we be the ones to put in print that our bus has dropped 50% in the last 12 months. I don't believe that is the case with all units! Let the water seek it's own level and we should not force it in any direction.
If you need to sell fast, you will drop the price. If you take care of your bus and don't have to unload it in a big hurry, the informed buyer will appreciate the TLC and pay more for that.
If something must be done with the price guide, make it go away, you can always bring it back under more favorable times.