Those textures are literally the exact same.
Again, the only differences are alpha/lighting/shadow which makes the "higher resolution" character appear more defined. More defined does not mean a higher resolution image is being used for the texture.
A higher res texture would be more intricate. For instances, scratches on the belt buckle, extra wrinkles in clothing.
Also, I'm sure the reason is those special lighting effects take much more GPU power which is why they're reserved for the cut scenes.