Per Unit Percent of Sales Selling price Variable expenses. Contribution margin $90 63 100% 70 30% $27 1. Fixed expenses are $30,000 per month and the company is selling 2,000 units per month. Required: 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? 2. Refer to the original data. How much will net operating income increase (decrease) per month if the company uses higher-quality components that increase the variable expense by $2 per unit and increase unit sales by 10%