Where a nonprofit corporation was only entitled to the same interest rate on a tax overpayment as other corporations.The 7th U.S. Circuit Court of Appeals affirmed a decision by U.S. District Judge C.N. Clevert Jr., Eastern District of Wisconsin.Medical College of Wisconsin, a nonprofit corporation in Milwaukee, received a refund of Social Security (FICA) taxes after the IRS ruled that medical residents were exempt from them until April 1, 2005. The IRS added to the refund approximately $13 million in interest but later …