Jerry,
The first question is what kind of transmission cooler do you have? If you have a leaking transmission cooler, that could account for the higher transmission fluid temperature by letting engine coolant into the transmission fluid. The 225 degree temperature is too high for freeway driving if you have an adequate transmission cooler.
If the engine is running at normal temperature, the transmission fluid is not contaminated, there are no air restrictions at an air to air cooler, and the transmission fluid change coincided with the increased operating temperature, I would go back to TranSynd. However, you need to verify the other issues first.
Gerald