I reset mine to Draw/Sheath weapon because it seemed like ever time I really needed to move fast I was getting locked on. But eventually realized that L1 -> R1 accomplished that too, so now it's set to Assist target. Arrow down 1x to tank's slot on party, hit L3, and I lock onto their target. I don't always use it but when I do it's great at eliminating 'Oh no which one should I target?' lag and helps with little things like not picking up adds in WoD trash mobs.