It's great to see someone really digging into the whole atmospheric visual mechanism in MSFS, great job! That's one area that I'm really not satisfied with, and it really is a problem of a green color shift in the whole sim. My suspicion is it may have to do with an environmental mapping texture, much like we had in FSX and P3D. I've seen screenshots of aircraft sitting on tarmac at an airport, and has horrid green reflections on the underside as if they were sitting on grass. But it's pervasive through the sim, as I take screenshots into Photoshop to do a color correction pass, and it always eliminates the green cast. Some of the ReShade settings available on fs.to also do the same thing, but I can't use them since I bought the sim from the store, not Steam. I'm really surprised no one at Asobo has touched on this yet. I think if you are in the visual arts it's pretty obvious.