The 54-year-old Cochran, also the 2010 winner at Prestonwood Country Club, closed with a 5-under 67 to finish at 17-under 199. The left-hander won the Principal Charity Classic in June in Iowa. He has five Champions Tour victories after winning once on the PGA Tour.
Frost finished with a 66. He missed a short birdie putt on No. 17 and also settled for par on 18.
Kirk Triplett was third at 14 under after a 68.
Gary Hallberg (66) was fourth at 13 under, and Michael Allen (70) and Anders Forsbrand (69) followed at 11 under. With the top-10 finish, Forsbrand qualified for the Greater Hickory Classic next week at Rock Barn.
Bernhard Langer, the 2012 winner, tied for eighth at 9 under. Langer, two strokes behind Cochran entering the round, had a 71. Charles Schwab Cup points leader Kenny Perry shot a 72 to tie for ninth at 8 under.