My Sears Lawn Tractor (917.270820) was running and cutting fine. I decided to change out the blades on my 42" twin blade unit. To do this, I drove it up a couple of ramps to access the blades. I changed the blades out and noticed that one side of the mower deck was cutting lower than the other side. This wasn't a problem before I changed the blades. The left side of the mower deck front is an inch lower than the right side.

I reviewed the owners manual for adjustment and followed the adjustment procedures religiously. I loosened the nut under the arm to a maximum amount and tightened the nut on the opposite side in order to raise the right side of the deck....the end result is a difference of an inch between the 2 sides. Before starting this process, I checked tire pressure on a level surface, as well as the front links measurements as prescribed in the manual. This all checked out. (I've actually performed this process 3 times to make sure)

So is there something I did unknowingly to the deck in driving it up onto the ramps ? I'm baffled and frustrated at this point. Can't figure out what to do. Need one of you experts to help me out. What did I miss?
Thanks,
John