Honestly in the real life nothing is pure bright white, even any white cars that you see on the street are some sort of "off white" which can subtlety blend into the environment. IMO debating the white in the scenes is irrelevant, the answer is inconsistent shades of whites. You will never see any valkyrie artworks in white as well.
I don't know why Yamato chose to have different whites on the TV and Movie schemes, but the point is having pure bright white plastic on a toy is a bad choice.