By default, only one tier will be used to calculate the item's price on a per unit basis when selecting Tiered Per Unit Pricing as the Pricing Structure. If, however, the Stepped Pricing checkbox is checked in the settings (shown in the screenshot below) the item's per unit price will use all tiers to calculate the item's price:
For example, if the first tier is $5.00 and the second tier is $10.00 with a quantity of 20, the unit price will be calculated as follows:
The first 9 calculated at $5.00 per unit equalling $45
The next 11 calculated at $10.00 per unit equalling $110
The Total Price of the item will be $155 which will calculate the Unit Price by dividing the Total Price ($155) by the Quantity (20) for a Unit Price of $7.75:
