Note
	Levy, [1913 Webster]: 3. To raise or collect by assessment; to exact by authority; as, to levy taxes, toll, tribute, or contributions.

Levies in Interchange are a way of defining multiple additional product charging such as taxes, handling, fees, and shipping. If you use Levies, the normal salestax, shipping, and handling tags are ignored (even when you use [assign]).

The Levy configuration directive defines individual levy sections (levy keys). The Levies configuration directive defines which levy sections will actually be honored.

Levy sections (key names) are unlimited and arbitrary; we use salestax, shipping etc. to cover most common cases, but you can put anything in there and have it work as long as the key names in Levies have a corresponding Levy definition.

Levies are a bit processor-intensive, and as such are not recalculated every time they are accessed. They can, however, be manually recalculated by using the check_status Levy parameter, as described in the Levy reference page.