Applying Luster on your Tank? The F*ck? You crazy? Luster is ONLY for leather areas, or you can also apply that to shine Plastic Surface. (say, The Dashboard of your Car, or Meterbody of your Bike ... not even your Side Covers)
It seems you are using some 3rd Class Wax on your bike which is why its not shining some areas the way it should do.
Check the "Bike Detailing" thread throughly by r1. You'll find many tips and tricks there.
DO NOT put boxes or satchels on your fuel tank. They are the main reason for such kind of scratches.
I use Cosmic and it hides such scrubs perfectly well.