In fairness, I'd say it's Ford lying to everyone. These trucks are simply overrated or the payload capacity is underrated. It's one of the two.

That being said, 10,000 lbs is really 3/4 ton territory. The salesman should have told you that.

A payload rating won’t guarantee towing stability, or a comfortable relaxing trip now will it? That’s what everyone seems to believe. “You have plenty of payload so you can tow a really big heavy trailer with no problem” is repeated constantly on the forums. Payload (TV GVWR) is just one of many ratings to consider when matching TV to trailer and it’s the consumers responsibility to understand the capabilities of they’re vehicle.

Fixed it for you.

Op, just an FYI that you need 20” wheels to have the 18400 lbs gcwr. If you dont it is lower. I believe its the same as the 2017 trucks at 17100 lbs.