Interesting. I was just fooling around in our new-to-us 2007 Designer and found the same thing. When the sofa frame folds out, there is a 18 inch void at the head of the bed between the frame and the wall. When the queen air matress is inflated, the top either hangs over the void, or the bottom over the end of the frame. What I found was that when the matress is fully inflated, it is stiff enough to comfortably support my head and pillows in the area over the void without no support beneath it. I had to actually lay on it with a pillow to convince myself. I just figured this was part of the design, although it does seem odd.