Hi Brian,
In my experience TVSII correctly exposes ISO/DXcoded 100, 200 and 400 films and as I recently discovered also ISO/DXcoded 3200film.
I don't know about 6400 films, because as far as I know they do not exist; but if you want to expose your ISO 3200film as ISO 6400, you'll have to set the exposure dial at minus 1.0 (-1.0 EV).
Of course, if you want to compare exposure of differing ISO-films, you'll have to set the exact same focal length as well as take measurements in exactly the same lighting conditions (so you'll want a tripod) - otherwise the comparison wouldn't be corret. [I'm sure you're familiar with all this textbook-exposurestuff!]
For instance, with ISO 400film a certain scene will exposed by the camera at 1/30th - F8, but that very same scene will be exposed at 1/250th - F8 with ISO/DX 3200film on board.
I don't know how they do it at Kyocera/Contax, but 99% of all TVSII's exposures are correct, provided you know how/when to use the exposure correction dial and/or the AE-Lock.
Good luck, Peter (the Netherlands)