Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Percent of Per Unit Sales $ 125 80 100% 64 $ 45 36% Fixed expenses are $85,000 per month and the company is selling 2,700 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,000, the monthly sales volume increases by 100 units, and the total monthly sales increase by $12,500? 1-b. Should the advertising budget be increased?