Sagging Slide Floor

[Nomadicchefs]

My slide is sagging in the middle. Not in the center, but in the middle lengthwise. I attached a picture in case I don't explain it clearly. The dotted line is where it's sagging. I know it's cheap ply board, and a replacement would be insanely pricey, but is this something I can fix? The supports/slide arms underneath are one each end, nothing in the middle. They are very sturdy, but the couch and the dinette pieces actually have quite a bit of weight via metal framing etc.