Bubba,
the DVE disc has more damn test tones than you can shake a 6 9's Silver cable at! It has tones for each of the 7.1 speaker options and then a "between" tone for each. So like a tone from/for between left main and center, center and right main, etc. They never explain why, but it's there - go figure.
I believe (but don't quote me) that DTS ES is actually a discrete 7.1 channels and DD-EX is a discrete 6.1 channels. If you have 7 speakers DD-EX just matrixes the 6th into two.
Also, as a last note DO NOT EVER depend on the receiver for proper calibration of your system!!! I cannot emphizise this enough. Unless you do it with a test disc from the DVD player you could be WAY off. I found this out the hard way myself after always figuring things were perfectly calibrated but never being that happy with the sound. Then I got Avia and for giggles did the audio calibration from there. Almost all of the settings are different than when done from the receiver / pre/pro. As further proof I was at a clients house last week, Sony receiver, did the calibration through the receiver (which sucked anyway because this Sony only gave you 4 tones, Left, Center, Right, Surround and also treated both surrounds as one for distance and delay purposes). Popped in Lord of the Rings, the Balrog scene. It was all score, very little voices or front soundstage action. I then calibrated using Avia, and had to turn up the center channel 10db!!! Mains had to go down about 2db and surrounds up 4db!! Couldn't have been much further off, but afterwords - sounded great!
Settings may be a little off for PLII but big deal - I'd rather have the real thing right.