Any truth to this;
"I have a 2015 F350 SRW, 2 wheel drive. A little bit ago I was talking to a guy that has the exact same truck hauling a huge Redwood fifthwheel. When I asked him about the limits of the truck and the weights of his fifthwheel, he said that he retired from Ford, and they reduce the number they put on the placard for the RAWR by about 20 percent. Said they (engineers) know that drivers are going to push the limits of the truck, so they just wanted to give them a little fudge factor.
Actually Ford reduces the RAWR on the F350 SRW more than 20 percent.
As Bedlam tells us "Ford's Sterling 10.5" axle has a 9750 lb rating".
Ford uses the 10.5" Sterling in the F250 and F350 SRW trucks with RAWRs from 6100/6290/6730/7000 lbs all depending on suspension/tires and wheel selections.
GM and Dodge/Ram does much the same with the 11.5" AAM rear axles rated at around 10k-11k lbs range that is used under the 2500/3500 SRW trucks.
Both have used RAWR numbers from 6000/6010/6200/6500/7000 lbs.
Both have rated the AAM 11.5 axle for their 3500 DRW trucks up in the 9350-9375 lb range.
AAM upgraded the 11.5" axle for the newer DRW Ram to a 11.8" axle with a 9750 RAWR.