Contribution Margin, Break-Even Sales, Cost-Volume-Profit Chart, Margin of Safety, and Operating Leverage Belmain Co. expects to maintain the same inventories at the end of 2017 as at the beginning of the year. The total of all production costs for the year is therefore assumed to be equal to the cost of goods sold. With this in mind, the various department heads were asked to submit estimates of the costs for their departments during the year. A summary report of these estimates is as follows: Estimated Variable Cost Estimated (per Fixed unit Cost sold) Production costs: