Hauler bed, to slope or not?

[jasong-TC]

Question,
Why are most Texas hauler beds sloped in the rear?
I'm not talking a beaver tail to load from, just a slope on either side of the hitch.

Pickup truck beds are flat and square with no contact issues.
Typically the 5th plate sits a few inches below the bed rails.

 

[Bob86ZZ4]

I suspect they do that so there is more clearance for the trailer when turning on un-even surfaces? A HDT (heavy duty truck) hauler bed is probably a bit wider than your average pickup truck? So having the extra width and height would be more likely to cause contact with the trailer, wouldn't it? Most of the hauler beds I'm seeing where they don't load a car from the back they are mounting the hitch way near the back of the bed. I'm told this makes it better for backing up and stuff. And it frees up more bed space for side loading a Smart car or cycles. Or building a drom box.

 

[jasong-TC]

Thanks Bob.
I was planning on putting the hitch all the way back for those reasons.
I've found K&W makes flat hauler beds.