On December 1, 2006, Cardinal Company, a garden retailer, purchased $20,000 of corn seed, terms 2/10, n/30, from Iowa Farm Co. Even though the discount period had expired, Sandi Kurtz subtracted the discount of $400 when she processed the documents for payment on December 15, 2006. Discuss whether Sandi Kurtz behaved in a professional manner by subtracting the discount, even though the discount period had expired.