I contacted the Cliff's Welding and here is the deal..
They alter the spring hangers. Our trailers do not have adjustable spring hangers for raising or lowering the trailer. Cliff's will cut the shackles loose from the frame rails, then steel channels (the height of the lift needed, i.e., 2", 4" 6")are welded to the bottom of the frame rail. Then they weld the channels.
I was quoted about $1000.00. If I had been able to get it to them yesterday, I would have had the coach back Thursday.
Hope this helps, we are getting ours done soon and will update.