Starting flatbed for the first time

Both. Distribution of the load across more of the trailer puts less stress on it. Your also carrying more of the load instead of pulling it.

 

They try to put the weight over the axles so the trailer frame isn't carrying it as much like as with a "belly load"; where it's loaded in the center between the axles. Sometimes it works, but you are also subject to more twisting of the trailer frame.

Evil is evil either way IMO.

 

There really are no rules. Loads are almost never identical. But you learn with experience and dont hit cat scales. If your hauling legal weights, the worst you get is a over axle ticket. Lots of time around here with steel, they just give you a misload ticket.