Hello Mohamed.
I read the linked thread and it doesn't really answer my question.
1) We didn't install any shipping methods yet, but as far as I understand, yes I can restrict them to minimal and maximum price, that is convenient, but where exactly can I link it with the discount percent on total order value and will it actually work out the way the discount is intend to? How will it look on the order checkout?
2) As far as linking the discount to a limit, I see a problem. Firstly, I would have to create several flat categories to all my products and the limits will most definitely conflict each other, not mentioning that the last scale of discount is restricted only by minimal price and I don't see any discount percentage in Limit's interface, as well as I can't see what does the Value column refer to - minimum or maximum.
Could, you, please, clarify me a bit more?