On my sig pic truck (traded) my hitch receiver rating for tongue weight was 800 on the bare ball, and 930 for the WD rating. That was exactly 10% of max towing weight of 9300 lbs. my tongue weight was around 1000 so I began the search for info regarding hitch upgrades. Turned out, the OEM Ford receiver was the same receiver used on all the trucks. Only the sticker changed to reflect the as-build ratings of that particular truck. I think the max tongue weight rating for that year was 1500 lbs. WD. But it was the same unit as mine and all the rest which were rated for less. Logic says it was based on the capbility of the truck more than the receiver itself.