Nice post!!!
The light acceleration is one of the hardest things to tune, and every car is a little different it seems to what it likes and dislikes.
IMO I think it has a lot to do with the ignition maps and the fuel octane.
I have seen some strange cells in maps that can't handle a higher load and have to have a lot less ignition advance. I think it has to do with poor air velocity that creates a poor fuel atomization and to some degree some fuel fall out.
On my car I can have it shift at a 1000rpm if I want (control over TCU) but what I have found is my car likes to be shifted at 2800rpm for the best FE results.
This took a ton of hours but it now way better fuel mileage then it did before.