Fairfield 332 large slide

We've had our rig for 3+ years and love it. At the end of our factory warranty, we encountered a substantial leak over our large slide. An approved service vendor worked with the factory service rep. The leak was due to a sagging roof on that slide. The remedy to fix the leak was to put an additional header board on the inside. This did fix the leak but the slide would not totally extend. Thus leaving a 3/4 to 1" high ledge on the inside floor of the slide. This has become a bigger problem (my wife) and I want to see if anyone has a suggestion as to how this could be remedied. Any ides would be appreciated.