big dave

I understand that a lockup converter will be better for street/highway use because of its ability to stop converter slippage when locked but what about at the track? When my car is on the dyno, midway through 3rd gear, the converter locks up and according to the dyno graph, drops rwhp a little bit before it starts to rise again. Does this mean that this actually hurts trap speeds. Will a non-lockup converter normally trap higher speeds or will converter slippage pretty much even things out?