How to setup or use some work-around to calculate Customer bonus / incentive at end of a campaign /

 Hi,

At end-of a campain / promotion period,  company distributes bonus (additional money) to some of the credit-customers. Eligibility for bonus depends on the item-quantity purchased by a customer. During campaign period, all sales are done on campaign-cum-promotion selling-price (lower than normal selling-price).

The items declared for campaign/promotion sales are assigned money-value-per-unit for additional bonus calculation. By the way this bonus has no relation with unit-selling-price. It is based on the quantity purchased and per-unit-bonus-value assigned to the item. For example, there are two items X1 and X2.

1- Bonus value (per unit) for item X1 is 1.5 USD

2- Bonus value (per unit) for item X2 is 1.75 USD