Tongue weight is measured when the trailer is level, loaded for camping and not hooked up to the tow vehicle. Tongue weight measurement is then used to determine the amount of extra weight you are putting on the tow vehicle. This measurement number can then be used to determine if you need a w/d set up to shift some of the tongue weight forward and back. Too low tongue weight and you will have sway, improper w/d set up and you will have sway. W/d is not meant to defeat sway, sway control is what you need for sway. W/D is meant to keep you trailer and tow vehicle level and to distribute some t/w, if needed. I do not need w/d for my Ram as my 350# t/w does not effect the Ram. I do however need it with my FJ Cruiser as the t/w makes it squat in the rear and I need to shift some of that weight forward. I purchased a Andersen Hitch which is w/d plus it controls sway. Sway as I said earlier is from too little tongue weight or an improper w/d set up.
Due to the pandemic, my life now exists of only 3 days, yesterday, today, and tomorrow. Everything else has been forgotten!