I finally called Mobil - sorry it took so long, but I've been way too busy lately. Anyway, the tech guy said that it is not possible to certify a fluid Dexron-III any longer, because it's an obsolete specification. It has been superceded by Dexron-VI. That's all old news, we knew that. So, then I asked why the new M-1 MVF ATF is not certified Dexron-VI, and the basic answer is that
Mobil-1 MVF ATF does not meet the requirements for Dexron-VI. Period. That's why it doesn't say "Dexron" anywhere on the label. They still want you to buy their non-synthetic Dexron-VI fluid for Dexron-VI applications, but make the nebulous claim that the M1 MVF should work in pre-2005 vehicles, they just can't formally put the Dexron-III approval on there. And, he didn't state if it did actually meet Dexron-III specs or not - I didn't specifically ask, but I bet he couldn't say, even if he did know the answer.
Bottom line -
Amsoil ATF still has "Dexron III" right on the front of the label. I'd much rather use a fluid that clearly says "Dexron III", instead of a fluid that recommends a different product! What's unclear at the moment is if Amsoil actually had their ATF approved & certified Dexron or not, whether it's II, III, or VI. Here's a link:
http://www.amsoil.com/StoreFront/atf.aspx
You can get a case of 4 gallon jugs for $144 (!) list price direct from Amsoil (that's enough for 2 Mercedes trans fluid changes). Yeah, that price is crazy. However, if you add the "preferred customer" option for $10, you get 'dealer' pricing, which drops the cost to $104, plus the aforementioned $10, plus shipping & tax. For me, it was $14 shipping, $6 tax, for a grand total of $134.27 shipped to my door. That's $8.39 per quart. I'm officially switched to Amsoil for my ATF now. I sure miss the old Mobil... first they mess up their M-1 oil formulas, now they hosed up the ATF as well. If they ever screw up the Delvac-1 formula, I'll be switching to Amsoil engine oil too...!