When New Orleans Mayor C. Ray Nagin explained in mid-December the administration’s decision to close most city buildings on Friday, he described it as a last-resort attempt to save the city money on utility costs and janitorial services. Budget document released by his office show a projected $100,000 savings on janitorial service in Municipal Traffic Court, Criminal District Court and City Hall and another $30,000 monthly on utility costs at 1300 Perdido Street, adding up to $460,000 annually.