I have the same question for my 2014 Edge with the factory towing option. From what I've read at etrailer,com, the hitch should have a label with two towing ratings for tongue weight and towing capacity, 1) for hitch only and 2) for use with a weight distribution hitch (WDH). If it only shows one tow rating (tongue weight and towing capacity) then the hitch is not designed for use with a WDH. My label only shows one rating: tongue weight 350 lbs, towing capacity 3500 lbs, so it does not appear to be designed for use with a WDH. The label is located on the bottom of the hitch. I've also looked through my owners manual and there is no mention about using a WDH.
I tow a 2400 lb tent trailer. The back of the car doesn't drop much, but just enough to raise the front end, which causes on-coming cars to flash their lights (thinking I have my hi-beams on). I'm not sure what qualifies a hitch for use with a WDH, but it probably has something to do with the way it attaches to the frame, or that it's a class II hitch.. Or maybe Ford did not want to provide this info for fear of owners overloading their vehicles.
Any comments about using a WDH would be welcome.
Thanks
Denis - Anaheim, CA
2014 Edge SEL
1997 Coleman/Fleetwood tent trailer