Hello just need help with this problem , because I believe I am doing it correctly but the answers are still incorrect.

Exercise 5-1 The Effect of Changes in Activity on Net Operating Income [LO5-1) Whirly Corporation's contribution format income statement for the most recent month is shown below: Total Per Unit Sales (8,300 units) Variable expenses Contribution margin Fixed expenses Net operating income 257,300 $31.00 19.00 157,700 99,600 12.00 55,900 $43,700 Required: Consider each case independently): 1. What would be the revised net operating income per month if the sales volume increases by 30 units? 2. What would be the revised net operating income per month if the sales volume decreases by 30 units? 3. What would be the revised net operating income per month if the sales volume is 7,300 units? 1. Revised net operating income $ 460,560 2 Revised net operating income S456 3. Revised net operating income 396.700