I am in need of a new toilet for my 190 Chevrolet 3500 Express. It came with a Thetford Aqua Magic IV Lo Profile 20810 model. They are only 12.5 inches from the bottom to the top of the seat (closed) and it can't be any higher than that or it won't fit into the bump-out for the front of the toilet or allow the toilet paper roll to fit so the door can shut. I am having trouble finding anything that short. Anyone else have had yours replaced? Suggestions?