Baam23f
The front speakers are 52" tall. And the center would sit well below. My impression is that the oratorio was designed with the HT in mind more then the MC music. So far I am listening multichannel music with four speakers.
Provided your DSP is adding back in the Center channel information to the L and R main speakers (phantom) then you are certainly doing the right thing in your case, IMHO.
A perusal of most recording studios will show that, for those with a surround setup, they all seem to prefer to mix/master with five speakers of the same type, with the mid range and tweeter drivers all at the same height.
At the end of the day, you have to ask yourself how many people have you ever seen listening to stereo with Left and Right channels at different heights from the floor, or one speaker turned upside down and the other the right way up?
Common sense should tell you what is best...inspite of the marketing hype and sales people which often advise differently on a center channel.(I wonder why?)
BTW: Kudos to Rives for telling things like it is, which just shows that some companies can be trusted to look after their customer's best interests....these companies obviously seek repeat business and word of mouth recommendations, rather than focussing on one time sales!