Slide out adjustment on Lippert above floor???

My new MH has a Lippert above floor slide out and I think it needs adjusting and the dealer says "NO". When closed, it has a much tighter fit on the side towards the rear than the front side. I can easily put my fingers on front side and not on the rear. I just measured it and the front is 3/4" and rear is 1/4". Should they be about the same? Dealer says they are fine and sealing.
In the compartment below the slide are 2 hex shaped rods coming down from the slide above. One has a cotter pin thru it and the other has a lock nut. The dealer says it's the adjustment. The lock nut was loose and about to fall off. They retightened it, but with it being loose can't if fall out of adjustment?