What is your interpretation of the changes to the contribution margin per unit and the operating income on account of the unit price charged to the distributor? At a current operating level of 100,000 units, the company will not have to turn away any of its regular customers in order to fill the special order. If it wishes to increase operating income by $3 per unit included in the special order, it only needs to generate a contribution margin per unit of $3 Thus, the selling price per unit included in the special order is $25 .