required information exercise 5-5 (static) changes in variable costs, fixed costs, selling price, and volume [lo5-4] skip to question [the following information applies to the questions displayed below.] data for hermann corporation are shown below: per unit percent of sales selling price $ 90 100% variable expenses 63 70 contribution margin $ 27 30% fixed expenses are $30,000 per month and the company is selling 2,000 units per month. exercise 5-5 (static) part 1 required: 1-a. how much will net operating income increase (decrease) per month if the monthly advertising budget increases by $5,000, the monthly sales volume increases by 100 units, and the total monthly sales increase by $9,000? 1-b. should the advertising budget be increased?