Shelhorse Corporation produces and sells a single product. Data concerning that product appear below: Selling price Variable expenses Contribution margin Per Unit $ 180 54 $ 126 Percent of Sales 100% 30% 70% Fixed expenses are $344,000 per month. The company is currently selling 3,900 units per month. Required: The marketing manager believes that a $13,000 increase in the monthly advertising budget would result in a 130 unit increase in monthly sales. What should be the overall effect on the company's monthly net operating income of this change? Change in net operating income