All the standard tax rates are already built into the system. Although there is provision for users to change them, it is recommended that they are left alone. If any of the rates change, the distributors will write to all registered users informing them of what the changes are and how much the upgrade will cost.
The tax factors are used in the tax calculation that are not applicable to a particular scale or taxable amount.
Consult the tax office's calculation specifications if you wish to know how each factor affects the tax calculation.