The U.S. government has told BMW to reduce the gas mileage estimates on window stickers of four Mini Cooper models. Testing by the Environmental Protection Agency lab in Ann Arbor, Michigan, discovered the overstated mileage. The vehicles affected are the 2014 Mini Cooper three-door and Mini Cooper three-door S models with manual and automatic transmissions. The EPA says it audited the Mini gas mileage and came up with lower values than BMW, which makes the cars. It's the fourth time in the past two years that the EPA has found discrepancies in the gas mileage estimates provided by an automaker. The Street's Scott Gamm reports from New York.