It should not drop it any more than it is now. The overload springs on the top probably do not touch the brackets until you hit a bump or have a slight load in the bed.
1. Broke down on the side of the road
2. On the hook of a wrecker
3. Sitting in back yards not running
4. Sitting in scrap yards
5. Melted down and returned as Kias
Sorry; couldn't resist.
EDIT, oh wait; you said where are my ford GUYS at.
another possible reason for the rough ride is that it is a short bed dually, no matter what you do that thing is giong to be rough. you could always do a ridetech rear setup, it would help. truck looks good though, good luck