Wet Runway Weight Correction on B737 NG

[falconer171]

I am afraid you're wrong there is weight penalty for slippery runway (which is wet) takeoff on 737 NG in PI section.
What I am asking is that, after we made the weight correction for Max Takeoff Weight for slippery runway, do we still have to make another slippery runway correction to the actual takeoff weight on DERATE setting (e.g. 22K) to select the speeds.