Ford Motor Co. lowered the fuel economy ratings for six 2013 and 2014 model-year vehicles, including the Fiesta subcompact car that has been widely added to fleets.

Ford verified the revised fuel ratings in an internal audit that was supervised by the U.S. Environmental Protection Agency.

Models with restated ratings include four Fiesta vehicles; the C-MAX Hybrid and C-MAX plug-in hybrid; Fusion Hybrid and Fusion Plug-in Hybrid; and Lincoln MKZ Hybrid.

Affected owners and lessees will receive a goodwill payment for the estimated average fuel cost of the difference between the two fuel economy labels, Ford announced in a release.

"We apologize to our customers and will provide goodwill payments to affected owners," said Alan Mulally, Ford's president and CEO. "We also are taking steps to improve our processes and prevent issues like this from happening again."

Ford worked with EPA as the agency retested the vehicles to determine the correct fuel economy ratings. Ford is required to correct fuel economy labels on affected vehicles within 15 days, the EPA announced in a release.

Cars currently in dealer lots will be re-labeled with new window stickers reflecting the corrected mileage estimates, says the EPA. Most labels will change between 1-5 miles per gallon.

"This issue highlights the need for continued strong oversight of the fuel economy labeling program," said Chris Grundler, director of EPA's Office of Transportation and Air Quality. "Consumers need to trust that fuel economy window stickers are giving consumers reliable and fair estimates of real world fuel economy."

Fleets registered 12,036 Fiesta cars in 2013, according to the 2014 Automotive Fleet Fact Book. In 2012, fleets registration the Ford Fusion Hybrid was 5,053 vehicles. The C-MAX Hybrid had 2,530 and the Lincoln MKZ Hybrid had 86 in that year, according to the 2013 Automotive Fleet Fact Book. The Energi versions were not included in the Fact Book.

The new fuel economy labels will be available in approximately six days. Ford has told dealers they can continue selling the vehicles until the new labels are received.

Approximately 200,000 of these vehicles have been sold or leased to customers in the United States, according to Ford.

U.S. EPA-Estimated Fuel Economy Label Ratings and Goodwill Payments