The following are examples of the ways in which a duty or levy under this Part can be fixed--
(a) by providing that the duty or levy is to be a specified amount,
(b) by providing that the duty or levy is to be an amount calculated in a specified manner (such as, for example, as a percentage of the gross revenue of the casino from gaming),
(c) by providing that the duty or levy is to be a specified "base" amount plus an amount calculated in a specified manner.