I'm not sure how this works, but if you require a lens that supports distance reporting, then I imagine it's going to be based on the lens being able to read the current focus position (as opposed to just being able to tell the motor to go front/back, with no idea *where* it currently is). If it works like that, then it's likely based entirely upon where the lens is focused, with whatever focus point is used, or wherever it has been manually focused to. Focus point expansion can mean using a point other than the main one selected. Metering mode shouldn't affect anything. Focus and recompose may give wrong flash powers, just as it may result in OOF shots.