Income Statements under Absorption Costing and Variable Costing If required, round interim per-unit calculations to the nearest cent. a. Prepare an income statement according to the absorption costing concept. b. Prepare an income statement according to the variable costing concept. c. What is the reason for the difference in the amount of operating income reported in (a) and (b)? Under the method, the fixed manufacturing cost included in the cost of goods sold is matched with the revenues. Under , all of the fixed manufacturing cost is deducted in the period in which it is incurred, regardless of the amount of inventory change. Thus, when inventory increases, the income statement will have a higher operating income