Thanks to the experts for your patience and the explanation. It sounds like I should only expect 313 SQM on the YEG-YYC leg, which would put me at 50,006 SQM for the year and allow me to squeeze through. But it certainly feels uncomfortable tight.
It sounds like there may be a chance I only get 100% on the YEG-YYC leg if it posts as Flex. And if the estimated distance YYC-PHX is out by 4 miles or more, I'll also fall short. Should I book a refundable YEG-YYC or YEG-YVR turnaround for late December just in case?