KAUFMAN, BOARD <KB> UNITS CUT QUAKER <KSF> STAKE Kaufman and Board Inc and its insurance subsidiaries said they lowered their stake in Quaker State Oil Refining Corp to 1,795,908 shares, or 6.9 pct of the total outstanding, from 2,120,908 shares, or 8.1 pct. In a filing with the Securities and Exchange Commission, the Kaufman and Board group, which includes Sun Life Group, said it sold 325,000 Quaker State common shares between Feb 27 and March 23 at prices ranging from 28.00 to 31.00 dlrs each.