I completely understand that DirecTV gave you bad info, even if you got bad info multiple times. It happens all the time and unfortunately it happens with too many businesses. I would not blame you a bit if you told them to shove the whole thing and move to Dish. Heck, why not. Just be aware that Dish is also likely to give you bad info at some point in their future. When you have kids answering phones, reading scripts and trying to get to the next person on hold as soon as possible the businesses are setting themselves up for these kinds of falls.
As to the DNS service itself, I am guessing that 16 years ago locals were not available in your area but they are now. If DirecTV follows the laws (rules, guidelines, whatever) they are not allowed to provide DNS to a homeowner where locals are available. "In theory" the same will be true when you move to Dish or All American Direct unless you don't provide them with all the details such as living in a house and not an RV.
I hope you are able to find a good working solution for your problems and you find a service provider that can service your needs.