Q. I am retiring under CSRS offset. In 2007, I worked as a temporary employee for four months. During that time I paid FICA, but not the additional 0.8 percent toward my retirement. OPM states that I need to pay the full 7 percent to get full credit toward my retirement. Given that the CSRS offset contribution is 7 percent, divided by 6.2 percent toward FICA and 0.8 percent toward CSRS, wouldn’t paying an additional 7 percent be a double payment toward FICA? Shouldn’t I just be liable for the 0.8 percent deposit? If I must pay a full 7…