Loco, all Dolby Digital will play through the rear CENTER channel so long as
you have EX decoding. All of it. Only DTS won't. So that means MOST material
will play 6.1.

And it's just a mix channel. If there were descrete 6.1 or 7.1 source
material out there it might mean something.
We've seen your little "theater" room. If you had a 30'x45' room with
effects speakers on the sides your rear center might mean something. Right now
I doubt if you can notice it. So quit knocking the guy for his 5.1.
S/V Express 30 "Ringmaster"
Trains are a winter sport