I saw the same thing when reading up. I'd give the company a call, ask them your specific question and be clear about your setup, etc. They should be able to give you a good answer.
I haven't heard of this hitch either so you might not get many replies back.
I would certainly call the company though and not ask your dealer. Not saying your dealer can't steer you in the right direction, it's just the company probably deals with things like this all the time.
Good luck and let us know what you find, if it's a new hitch it may grow in popularity in here and down the road others might have the same type of question.
I wouldn't want to turn off the sway control personally, if I was driving in rainy weather, it's probably accompanied by wind which would mean you would want the assistance of a sway control. However, obviously, there must be a reason behind the manufacturer's statement.
2012 Keystone Sprinter
Still sticking around for the good people and advice.