i think it's normal to have color shifting at that angle, and since the whole screen is affected, i guess it's normal.the color starts to change at 45°.
the more neutural color the more obvious it appears green. i.e. it happens more to the menubar, window title bar, grey desktop image than to white windows background.
it affect the whole screen instead of just the bottom.
Calibrate it. The default ColorSync profile has a very definite green push. And since you have the LG panel, you might try the profile I created with a hardware calibrator. See this message for details.My new MBP has a GREEN hue if viewed from the side. I've read a lot about the "1/3 screen yellow tint" problem. Mine is actually greenish. Is that same problem or something to ignore?
BTW it's LG screen.