18) Naumann Corporation produces and sells a single product. Data concerning that product appear below: Per Unit $ Selling price Variable expenses Contribution margin 180 36 144 Percent of Sales 100 % 20 % 80 % $ Fixed expenses are $100,000 per month. The company is currently selling 1500 units per month. Required: Management is considering using a new component that would increase the unit variable cost by $50. Since the new component would improve the company's product, the marketing manager predicts that monthly sales would increase by 700 units. What should be the overall effect on the company's monthly net operating income of this change if fixed expenses are unaffected? (Negative amounts should be indicated by a minus sign.) Change in net operating income