As I suggested to all in your previous thread......
Watch your DEF closely.
carry a full 2.5 gal. container with you.
As for suggestions, if I had three 5-gal. containers, I would siphon the DEF tank out to see what you are dealing with. Put say 6-gal DEF back. Then start the engine, place on fast idle and start siphoning back out while watching the DEF gauge on the panel. I would poke the throttle frequently to see if you can get the rpm's up.
Maybe not a perfect scheme, though.
As for another thought, I do not believe that the engine getting a lack of DEF, lowers its power by its own (aka such as running out of fuel. The DEF measuring electronics probably is the commander. Could be that when you had the problem and 4 hour wait, maybe it wasn't your DEF at all. Sorry for throwing another torn into the issue. - Hank