yeah.. Its was a long time ago.. so its a little foggy.. But i got my countryman around 1977 or so maybe '76.. I bought it after i did my first record for Columbia Records. All the studios had them. I doubt that anyone can count how many Huge hit records were made using the Type 85 FET DI in all of the major recording studios. Not including all the non hit records too. The Type 85's are still in use today at top US studios Ardent, Village , Record Plant ,Paramount in LA and NY.. .
No revisions on the Type 85 except for the painted Logo. Still the same as it ever was
Just because it it says it type 85 doesnt mean that is the year it came out..
I also believe that i saw the TYPE 10 out in the wild earlier than 2010. So i dont think that your theory works out with the numbering system you created.
You make many assumptions.. Not good on TB...

Also, just because something is new doesn't mean its always better.
However The type 10 is a nice box.... But that also doesnt mean the type 85 is junk or obsolete ..