"In Evaluative metering mode, the metering is always weighted toward the selected AF point. That's true on the 1D X, it's true on a Rebel/xxxD.
What the 1-series bodies have that lower bodies do not is Spot metering linked to the AF point."
Thanks, neuroanatomist. I never knew this was a fact, but after reading your reply, I did find an article on Imaging Resource confirming what you wrote.
I've often metered off of a face (while in evaluative mode), then recomposed to put, say, a corner AF spot on the face, and gotten unexpected results. Finally knowing what is happening should be a big help.
Thank so much for contributing helpful replies and info as often as you do.