Well, Lexicon seems to try hard to please their customers.....
There is no 192Kbit digital S/PDIF output on the MVP851. Unlike the Denon 5900 or the Pioneer DV59-AVi it also does not have a 1394 interface which means you will never be able to get 24/192 out of the MVP851.
If you connect an MVP851 to an MC12 the best you get is 24/96. This is exactly what you get on an SP1.7.