So here's what I did:
1) I called the 3 Allison service centers in my area, per MJFZ and Triker's suggestions.
One of them had Transynd for $38/gallon.
One did NOT carry Transynd, but had Mobil Delvac (on the approved list) for $34/gal.
The third service center had "an Allison approved Trans fluid" for $30/gal -- but bring your own containers. I asked him who manufactured the fluid, and he said the container said "PetroChem", and he assured me that they ONLY use Allison approved oil since they are an Allison service center.
I struggled with the cost differential as well as the likelihood that I would ever put 30K miles on my MoHo, and then bit the bullet and went to the first one and bought the Transynd for $38. I tried the "military discount" and "Senior citizen discount" with them, but they said it normally sells for $60/gal. I said that I found it on line for $34, but the shipping brought it up to around $39.
So, that's over with.
I'd suggest what I saw some others do -- when you're at a truck stop that has it for $34 on the shelf -- buy a gallon or two and store it, just in case/or when you need some in a hurry.
Thanks to all for the decision assistance.