Yes, because that 500lbs of tongue weight will pull another 200-300-ish off the front axle and plant it square on the rear axle.
200 may not sound like much but you're adding another 700-800lbs to the rear axle overall.
Back to your assertion that it "has" to be better than the F350, well yes, it very well might be. It also might be worse.
The reason there is so much argument over the numbers is, you never know. You never know how the truck will react to being overloaded. You never know how tolerant the potential driver of the rig will be of the driving qualities of the rig. You never know the skill level of the potential driver (Aren't we all the best drivers in the world, regular Mario Andrettis?).
Sure, things can go belly-up no matter what you do, but your best chance of success and satisfaction is to stick with the manufacturers' numbers if nothing else is known. After that it is up to you to determine how much extra weight you want to carry.