If I understood Glock's post correctly, I think he got it half-right.
AFAIK, Glock is correct in that the 663 cannot matrix the bitstreams from advanced codecs. However, it CAN with mch PCM (if player has the codecs already unpacked/decoded).
The above is perhaps the biggest, single reason that I crossed off the 663 from my shopping list.
So, wspann, while it might be a bit of a hassle, you can leave it as bitstreamed all the time, and for the rarer occasions of having a natively recorded 6.1/7.1 track, change the Sammy's output as decoded PCM. Sorry about the news if it bums you.