Huh? You can't be serious. You think there's some point in attempting to recover from a shot five stops underexposed? Hell, even three stops underexposed is insane. But five?
totally serious, but you misunderstand.
i'm not asking to recover a -5EV shot to 0, or the -4 or the -3.
I'm asking you to try this and see how far you can push your 5d2's -3, -4, or -5EV shot before visible pattern noise shows up on a smooth subject. IT IS SIMPLE.
In the real world this can by sky, water, various man-made surfaces so it's completely appropriate.
Sorry, I'm not accepting any blame for the camera's metering. i didn't build it or calibrate it.
If you know how it works, look at the subject and shooting conditions, you should realize why.
Apparently you did not read/comprehend all the info provided. Take more time to understand than to ridicule, it's better all around.
if you have a 5d2 and care to contribute, follow the instructions. If not, sit back, have some popcorn and join the rest of the peanut gallery to watch the drama. 