Thank you that adjustment is on my list actually, I'd like to smooth out a tad more.Thinner fluid may need a slight up adjustment to match the shifts with thicker fluid. With more pressure it feels like it holds the gear slightly longer then shifts hard to the next gear. Not sure if it's actually quicker but it does give that feel. generally you want more pressure for really heavy hauling.
Also before I went though I saw lots of references to guys losing trannys at fluid changes but I only saw one person named for one tranny. And lets face it trannys wont last forever stuff wears out and who knows how good a job Red River and such did the rebuilds....if any. I dont think anybody but Allison really knows since they start new, come in for service, get rebuilt, verify failed parts, and go back into the world. Allison put out a fluid chart for our rigs based on temperatures and such so its best to follow that. My 2 cents.
But we all use our rigs differently too. 10WT, Transync, 15-40, and Dextron are all aproved fluids so we make our best decision and take our own risks.