Suppliers frequently provide quantity discounts to customers who place large orders. An incremental quantity discount provides a discount to all units purchased beyond the applicable price breaks, but units purchased before the price breaks still pay their respective higher prices. Consider the following incremental quantity discount schedule:

Size of Order .............................................. Price per Unit
0−400 ............................................................ units $40.00
401−1200 ...................................................... units $40.00 for the first 400, and $38.00 after that
≥ 1201 units .................................................. $40.00 for the first 400, $38.00 for the next 800,
                                                                            and $30.00 for any purchased beyond 1200

Build an Excel model that returns the total purchase amount and the average price per unit for any supplied order size.