WXII is reporting that some residents at Lazy Acres Mobile Home Park here in Lewisville may have been overcharged for years by Duke Energy.  Apparently Duke charges a higher rate to homes that aren't 100% electric, and some of the mobile home residents say they were charged that rate despite being entirely electric.  The difference is less than a penny a kilowatt hour, but for people on a fixed income that can make a big difference.  One resident said she'd lived at Lazy Acres for 25 years and had been paying the higher amount the entire time.  If that's true then Duke could be ponying up a hefty refund for her.