Frost, meanwhile, shot a sizzling 6-under 66, matching the low round of the week, and Cochran registered a 67, knotting all three golfers at 7-under 209.
Moving into a share of fourth place were Corey Pavin and Barry Lane, each of whom fired 3-under 69s to end at minus-6 at Walton Heath in Surrey, England.
Second round co-leader Lee Rinker stumbled to a 2-over 74, falling into a sixth-place tie with Chip Beck (69) and Mike Goodes (71).
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