Bloomberg News: Insurers offering Medicare health plans were overpaid by the U.S. as much as $3.1 billion in 2010 because the government miscalculated how sick beneficiaries were, federal auditors said. UnitedHealth Group Inc. (UNH) of Minnetonka, Minnesota, and Humana Inc. (HUM) of Louisville, Kentucky, are among the insurers offering coverage to people 65 and older through Medicare Advantage, an alternative to the traditional federal health program for the elderly and disabled. Democrats have criticized Medicare for overpaying companies for Advantage [...]