Do you have an 8 speed with issues?The Ford 10 speed was built with GM. The truck is the same transmission.
Note Ford used their own tuning and programming for their engines as GM did theirs.
We also need to consider this not all of these transmissions are in the same condition. Some have shuttered longer or harder and may have done clutch damage that has hurt the converter.
The new fluid will fix most of these but some may be too far gone to reclaim.
As to how long will this work? Time is the only way to tell. GM and Mobil I am sure did a lot of Dyno time and cycles but the real world is the real test. I am sure they also has some road testing going on too.
Fixes like these are not always fast nor easy. They take time to find and we have seen GM struggle with a remedy and not all were cheap with full replacement of the transmission or converter. Even the fluid flush runs about $650 per truck.
I believe GM May have some solid info showing this will work in most cases when they changed the fluid at the plant. The Class Action means little as they will still end up paying a settlement to make them go away and you will get a card for $200 off the next new vehicle you buy while the Lawyer goes on vacation in the tropics.
For now this is a matter of faith, time and vigilance and watching how this goes.
What we do know so far is most transmissions have reacted in a very positive way shifting better than new in most cases.
Note too some vehicle not solved with fluid may also have other issues creating the problem.
The bottom line is none of us have all the fact nor will we get them. We need to work with what we have and follow along and report here what we do know. If this remains good we will see less complaints and positive reviews. If not we will see more complaints here.
For now flush and drive and keep an eye open but don’t over think this.