U.S. automaker Ford Motor Co. said it would send refunds to C-Max owners to make up for overly generous fuel efficiency claims. Ford said it would drop the rating on the C-Max, a hybrid vehicle, from 47 miles per gallon in combined city and highway driving to 43 mpg, The Wall Street Journal reported Friday. While some disgruntled customers have filed lawsuits, Ford said it would mail $550 checks to C-Max owners and $325 to persons leasing a C-Max. The company has sold about 32,000 C-Max vehicles, the Journal said. Ford explained that it tested the mileage using a C-Max engine and a Ford Fusion body, even though the Fusion\'s body shape is not the same as the C-Max. The Environmental Protection Agency, however, allows for that kind of crossover testing, given the vehicles use identical transmissions and engines and are in the same weight class. The EPA did not fault Ford, nor fine the company. \"This is allowable under our regulations. What we know now is that even small changes on high-fuel-economy vehicles produce big differences in the results,\" said Chris Grundler, director of the EPA\'s Office of Transportation and Air Quality.