not sure what im doing wrong to calculate the increase in income by 10%. thank you!

Vice President for Sales and Marketing at Waterways Corporation is planning for production needs to meet sales demand in the coming year. He is also trying to determine how the company's profits might be increased in the coming year. This problem asks you to use cost-volume-profit concepts to help Waterways understand contribution margins of some of its products and decide whether to mass-produce ary of them. Waterways markets a simple water control and timer that it mass-produces. Last year, the company sold 635,000 units at an average unit selling price of $4.90. The variable costs were $1,866,900, and the fixed costs were $846,328. (a1) What is the product's contribution margin ratio? (Round ratio to 0 decimal places, e.g. 25\%.) What is the company's break-even point in sales units and in sales dollars for this product? Break-even point in units units Break-even point in dollars eTextbook and Media Attempts: unlimited (a3) Your answer is correct: What is the margin of safety, both in dollars and as a ratio? (Round ratio to 0 decimal places, e.g. 25\%.) Margin of safety in dollars $ Margin of safety ratio % If management wanted to increase its income from this product by 10%, how many additional units would have to be sold to reach this income level? Waterways would have to sell an additional units