After several weeks, the Dlr service mgr indicated that Lippert wasn't going to do anything further and the Dlr Srv dept was too busy to help.
So, after doing some online searching, I found "equa-flex" balancer made by Lippert on etrailer.com. The part gives an additional 1" clearance, which appears to be enough distance so the shackles no longer nick the propane line and also the tires aren't bottoming out. I did a 30 mile test run and all seems good.
Btw, on the test drive I weighed the trl, 7500 with no water, refer food or clothes.
Lipperts claim that the trl was overloaded is not correct. It's just bad engineering.