3. Taxing
Interchange allows taxing in a number of ways.
Simple salestax.asc table
The SalesTax directive is set to a form field or fields for user input, and those form fields are used look up the tax rate in salestax.asc.
Fly tax
Another simple tax method. A series of Interchange Variable settings are read to develop a salestax rate for one or a few localities, usually a state in the US.
Salestax multi -- VAT taxing
The country and state tables are used to develop complex VAT or salestax rate calculations based on country and state, possibly with different rates based on product type.
Levies -- multiple levels of tax
Using the Levies setting and the Levy structure, any or all of the above methods is used to implement one or more taxes.