Defense Department officials are re-upping their commitment to performance based logistics contracts as a way of bringing equipment upkeep costs down, but advocates of the strategy are facing an uphill battle in driving the change, according to officials and documents. Leaders have renewed their emphasis on PBL contracts in recent weeks, following Pentagon acquisition chief Frank Kendall's Better Buying Power 2.0 initiative issued last November. "There is sufficient data on the effectiveness of PBL at reducing cost and improving support...