The federal government wrongfully paid Medicare Advantage programs almost $70 billion, mostly through overbilling between 2008 and 2013, according to a new report. The Center for Public Integrity released the first of its four part investigative series Wednesday on Medicare Advantage payments that examines the use of risk scores used by providers to charge the government more for sicker patients. CPI found between 2007 and 2011, scores for Medicare Advantage patients grew twice as fast when compared to ordinary Medicare patients in more than 500 counties. The report cites government audits of six Medicare Advantage plans in 2007 alone with nearly $650 million in overpayments.