I think I understand now, since there is no direct magnification from the Taracs, they don't alter the mil value as the mil values are a direct result of magnification, not of shifting the image. Optical physics have always given me a little bit of a headache, no pun intended.
having used the trybe one extensively, my feedback if you're planning to break into that arena:
The trybe unit has its own zero settings to realign it to the primary optics train, which works pretty well, I think my biggest gripe about it is the attachment method, which is a fine pitch thread that can be difficult to time correctly when reattaching. Something like a miniaturized camera mount (like the oooold pentax K lens mounts) seems more suitable for the task of keeping things aligned while being easily removed/reattached.