Data concerning Lemelin Corporation's single product appear below: Percent of Per Unit Sales Selling price $ 230 100% Variable expenses 115 50% Contribution margin $115 50% The company is currently selling 7,000 units per month. Fixed expenses are $581,000 per month. The marketing manager has proposed a sales commission of $20 per unit. In exchange, the sales staff would accept a decrease in their salaries of $113,000 per month. (This is the company's savings for the entire sales staff.) The marketing manager predicts an increase in monthly sales by 300 units. What should be the overall effect on the company's monthly net operating income of this change? increase of $806,500 increase of $107,000 O decrease of $224,500 increase of $1,500