I never liked how this shot looked either. It always bugged me how there seemed to be a obvious line down the center where the existing shot was put next to the new shot. The colors and lighting just doesn't match. All the super orange mirror reflection just abruptly ends and the old white floor starts. Even the pattern in the floor does not line up.

I think that as far as appropriate lighting for this shot, the orange reflection should completely go and be replaced with the original white floor, with reflections intact. The 'sun' appears to me to be setting, so its light should be coming from the bottom of the screen and shinning up (kind of like the background shows). However, the reflection on the ground implies that the sun is higher in the sky, shinning down on the floor.

But even if the 'sun' was shinning directly across (i.e. it is level with the floor), it would be blocked by all the buildings off to the left that are off screen and still wouldn't be seen in this shot. However if it was the tallest building in Bespin to escape this detail, the sun would be reflecting all the way across the floor and not stop half way.