also its possible the reason different fruit combos give same color is because it maybe not have a TRUE max maybe after so maybe you go over the number and restart at bottom "most likely not". i think it follows the "tier" of colors like on the dye menu so after you get that certain color.lets say dalamud red adding another apple or apples tell you get the plumage message it should go up to red rust dye at least im hope it is.
"with add and or renamed colors" so just because the menu doesn't have a color doesn't mean im wrong just that its an added color or renamed. after this test im going to lighten and darken them again using one or two or three tell it says the message once if im right then they should change in color after seeing the message once. if im wrong they should mostly be the same color.