I have a 2006 60" super z with a XR-7 deck. I always check the blade height with a tape measure to be sure its set right. The other day we got done cutting and the deck was set at 3.5". Today the setting is still at 3.5 but when my guy made the first pass around the yard I had to stop him. I could tell it was lower. I measured it and it is now cutting at 2.5" when the pin is in the 3.5 hole ???? what happened from one day to another that changed the height ?