I changed the term after the fact because technically the definition of the expression means, searching for something in vain. So a waste of time looking. Even though Dex II/III old spec now, and superseded even by GM to more current specs ( Dex VI), it can still be found. I note though that even the Toyota fluid says formulated to "replace" DexII/III..... IMO, that's a bit vague. Leaves open that the Toyota fluid 'could' be a more current Dex spec, Dex VI ?
As for MV ATF's, I posted a link to research/data based conclusions on their use. I find those types of conclusions and information much more meaningful than analogies unrelated directly to the topic.
After reading this board on Synthetic based ATF and thier lower starting viscosity, I've become convinced of their greater sheer stability than mineral based ATFs like DexII/III. GM says Dex VI is appropriate for use in Dex II/III applications.
All that said, your rides and if using Toyota labeled ATF makes you more confident in the results, that's what you should do. To each their own.