Each customer has a price band set in the Customer Address Book. Sales and Credit Note without a Customer ID always get the Retail price band.

For additional price bands, i.e. not Retail, Trade, Factor, Wholesale. There can be a base price band that is used when not specific price for this price band is set.

Each price band can have multiple quantity breaks. The price is taken as the prices from the highest quantity break less than or equal to the row quantity. Note: if you the same item exists multiple times on the same sale, each row is considered individually.

If the customer has a special price exists for the item, this price overrides the list price at this point. Even if the special price is greater that the list price, the special price takes precedence.

A promotional price matches if the current date is within or equal to the start and end date ranges. Either the customers price band matches the promotional price band or the promotional price is for all customers (shown with a *) If the promotional price is less that than either the Special Price or List Price, the promotional price is used.