Contribution Margin Analysis The actual variable cost of goods sold for a product was $40 per unit, per unit, while the planned variable cost of goods sold was $47 per unit. The volume increased by 2,300 units to 28,400 actual total units. Enter all amounts as positive numbers. a. Determine variable cost quantity factor. $ Increase in variable cost of goods sold b. Determine the unit cost factor for variable cost of goods sold. $ Increase in contribution margin