I would thing that the crown is designed to handle larger payloads and gets flatter as you load up the truck. just have to buy a heavy enough caper to make it flat I guess..
serioulsy though, I have never seen a pickup truck with a crown designed into it, just highway class 8 trailers and some real long car haulter type trailers you pull behind your 1 ton. if there was a crown in my bed, I would be taking it in under warenty.
Steve