Required information [The following information applies to the questions displayed below.] Data for Hermann Corporation are shown below: Per Unit Percent of Sales Selling price $ 130 100 % Variable expenses 78 60 Contribution margin $ 52 40 % Fixed expenses are $86,000 per month and the company is selling 2,800 units per month. rev: 06_04_2020_QC_CS-205709, 06_18_2020_QC_CS-216765, 07_14_2020_QC_CS-216765 Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,100 and monthly sales increase by $19,500? 1-b. Should the advertising budget be increased?