The following monthly data are available for the and its only product, Product AJ: Total Per Unit Sales (500 units) $137,500 $ 275 Variable expenses 55,000 110 Contribution margin $ 82,500 $ 165 Fixed expenses 52,800 Net income $ 29,700 Required: a) Without resorting to calculations, what is the total contribution margin at the break-even point? Management is contemplating the use of plastic gearing rather than metal gearing in Product SW. This change would reduce variable costs by $15. The company's marketing manager predicts that this would reduce the overall quality of the product and thus would result in a decline in sales to a level of 450 units per month. Should this change be made?