Is it possible to get it to meter using the selected AF point instead of the center of the frame?Nope unfortunately not thats the realms of 1D bodies only
I know it's not supposed to be able to do that, but sometimes it does. For instance while sitting in a dark room and shooting down a well-lit hallway, it meters down the hall way with center AF point, but meters for the room when using the right-most AF point (on wall of dark room).
Yes, but that's evaluative metering weighting the exposure toward the selected AF point. It's not the same as spot metering. Does it give similar results in some situations? Yes...but then, a stopped analog clock shows the right time twice per day.