Re tested by Allison (or any other manufacturer)
If they test it, and approve it then when (if) the transmission breaks down under the warranty period they have to make good.. If they do not test it then they can say "Oh, Unapproved Fluid" and your lawyer, and theirs, both go out and buy a new yahat. (After all who wins in a civil case... The lawyers of course).
Would I put the cooler on if doing that level of work, YES up to a seriously frozen point (Allisons tests their designs at temps as low as -40, possibly lower) I'd have to say cooler is better so go-4-it even if the tranny is runnign normal now. There is only one way it can hurt, if it's poorly made and blows a seam.
Home is where I park it!