Hello masonair. Hope we can get the forums serving your needs!
All Airstreams after 1962
use a 2 5/16" ball. A 10,000 pound rated shank is the size of your thumb -- you're probably using something like this already if you have weight distribution/antisway gear attached to your A frame.
Releasing isn't smooth every time for me either. That seems to be the case if the slope puts the back-inside of the hitch up against the ball. Hitching up and unhitching are smoother if the ball is at the front of the space inside the hitch as you raise or lower. If you're using a 2 5/16" ball, you could maybe confirm this for your case by seeing if it works any better on level ground. Just a thought .... don't know that's exactly what is happening in your case.
What size ball do you have?