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?