YS,
Thanks for the feedback. No, my Cat I ILS approaches were all done on "Altimeter Setting/ QNH". QFE is not used in Canada, and even if it were, you cannot wind the subscale far enough to get Zero feet at Calgary (3550'). I know, I tried once on the ground out of curiosity
It is interesting that there is no reference at all to Decision Altitude in the Canadian AIM and I have never heard the term used, but in practice of course, as you said, you have to add the DH to the TDZE and end up with a DA anyway.
I42