Exercise 7-7 Riggs Company purchases sails and produces sailboats. It currently produces 1,230 sailboats per year, operating at normal capacity, which is about 80% of full capacity. Riggs purchases sails at $278 each, but the company is considering using the excess capacity to manufacture the sails instead. The manufacturing cost per sail would be $97.73 for direct materials, $81.23 for direct labor, and $90 for overhead. The $90 overhead includes $78,200 of annual fixed overhead that is allocated using normal capacity. The president of Riggs has come to you for advice. "It would cost me $268.96 to make the sails," she says, "but only $278 to buy them. Should I continue buying them, or have I missed something? Prepare a per unit analysis of the differential costs. (Round answers to 2 decimal places, e.g. 15.25. Enter negative amounts using either a negative sign preceding the number e.g.-45 or parentheses e.g. (45).) Net Income Increase (Decrease) Make Sails Buy Sails Direct material Direct labor Variable overhead Purchase price Total unit cost$ Should Riggs make or buy the sails? Riggs should the sails