The very long and detailed linked discussion eventually morphed into the development of the VIP / Happy Hour Tutorial:
If you follow that Tutorial, and try to understand how it works, you can remove or skip the portions that have to do with Happy Hour so you are left with VIP-Level Discounts only.
You could certainly apply fixed and percent discounts based on Customer Levels, but you will need 2 Entity fields to define them, and 2 Discount Types, which you already mentioned.
It won’t be possible to know why your setup does not work unless you post screenshots of what you have done.