DT12's HDTracks were the same master, just the volume pulled down so not that many samples hard-clipped as in the CD version.
You keep saying that, and yet it's at the very least misleading and in my opinion plain wrong. They used the same source audio, but since the step that affects the volume that you're talking about is obviously still part of the mastering process, they most definitely did NOT use the same master. Call it pre-master, call it mix or whatever, but the "original" (usually called the "master"!) used as a reference for duplication of the discs or files was FAR from the same.
And "just the volume pulled down" is also misleading, as to a less knowledgeable reader it might suggest that anyone could just to the same with the CD - and we know the problem of the CD sound is the very fact that they can't. The CD was pushed to the max in such a way that audio information and fidelity was lost.