The United States on Monday sued New York City and Computer Sciences Corp, accusing them of defrauding Medicaid into making millions of dollars of improper reimbursements by exploiting a computerized billing system that the company designed. According to a complaint filed in U.S. District Court in Manhattan, the defendants took advantage of the system's automatic default settings, enabling the city to improperly boost the amount and speed of reimbursements for services provided to infants and toddlers with developmental delays.