A caveat here is that as you've seen the actual film that's rebranded as "Ultrafine" has the potential to keep changing, it seems dependent on what they can get and rebrand and/or what's cheapest - so, if you intend to standardize on 1 film, you may need to purchase a large quantity of it now, or take your chances on the actual film stock changing on you.
A couple of years ago I asked them about this, my concern being I wanted to standardize and didn't want to keep having to adjust development times/procedure for new films repeatedly.
My emails to them about this were ignored (while a prior question about shipping to Canada was answered, albeit slowly), so it seems they are not eager to share exactly what it is at any given time.
Contrast this with Freestyle, who give each different film a slightly different name (Arista EDU vs. Arista EDU.Ultra vs. Arista Pro) and are generally forthcoming about each films provenance (except for the newish Pro line, apparently, but relatively easily reverse engineered).
Caveat emptor, I suppose.