Pretty sure:
1. Ford manual does not say "don't use WD".
2. Ford is spec'ng minimums--used to be that WD would be required to haul over a certain weight such as 12,500 on my truck--now that has gone on up to higher weight.
3. WD doesn't interfere with anything, but surge brakes will maybe mess with the anti-sway.
4. Ford built in anti-sway doesn't kick in until you are about to go out of control. You still need to set up your trailer to prevent sway. Suggest the OP use some type of anti-sway at the hitch and not wait for emergency truck reactions.
