I can't seem to get the correct answer for the first part of the question.

It say correct on everything but the $1300.

6 Part 1 of 2 Required information Exercise 6-5 Changes in Variable Costs, Fixed Costs, Selling Price, and Volume (LO6-4] (The following information applies to the questions displayed below.) - 0.62 points Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Per Unit $ 130 78 $ 52 Percent of Sales 100% 60 40% eBook Hint Fixed expenses are $86,000 per month and the company is selling 2,800 units per month. Print Exercise 6-5 Part 1 Del References 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? Complete this question by entering your answers in the tabs below. Reg 1A Reg 1B 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? (Round any unit calculations up to the nearest whole unit.) Net operating income decreases by $ 1,300