It may be that you have proved that your system is better at surround sound that at stereo. Repeating the experiment in a 2 channel only environment might yield very different results (it did for me).

Also worth mentioning that when I have compared DVD's to CD's using the 44.1/16 bit soundtrack on the DVD the CD has generally sounded way better. case in point Elton John double album of greatest hits which I have on DVD, CD and vinyl. The DVD is so bad in comparison to the other 2 it aint funny.

I have other examples (but cant remember them as I type):

As for your DTS throughput figure - that is for 6 channels of audio as compared to CD's 2 channels. DTS does seem to sound better than the equivalent DD5.1 tracks but I am not sure for music it beats CD (in 2 channel format).