the issue is at all levels but most noticeable at the highest tune. What I do is disconnect both battery cables and then the "intelligent" POS resets and all is good for a while. I think the way to go on this thing is an engine and tranny tune. The learning capability of these things seems to be an issue. This is my first auto in a diesel and I am not impressed. I do drive in flat and then mountainous terrain though so it is probably partially my driving habits too. With my 6 speed manual this was never an issue.
As for the tunes, I found the highest was better than the stock, economy, towing and the first power setting. I tried all of them on a 10 hour round trip drive I was doing over and over and I would switch each time I went. for me it is either stock or the top tune it came with. The others just did not seem to do much on mileage which is why I bought it to begin with.