5.5 pts Thornbrough Corporation produces and sells a single product with the following characteristics: Per Unit Percent of Sales Selling price $ 220 100% Variable expenses 44 20% Contribution margin $ 176 80% The company is currently selling 7,000 units per month. Fixed expenses are $901,000 per month. The marketing manager would like to introduce sales commissions as an incentive for the sales staff. The marketing manager has proposed a commission of $11 per unit. In exchange, the sales staff would accept a decrease in their salaries of $65,000 per month. (This is the company's savings for the entire sales staff.) The marketing manager predicts that introducing this sales incentive would increase monthly sales b 300 units. What should be the overall effect on the company's monthly net operating income of this change