But it will not make a difference to your performance calculations so it does not really matter.
I think I would take issue with this thought. The idea behind grooving is to drain water from what otherwise would be a flooded runway surface. Wet and flooded runways probably need to be viewed quite differently from the point of performance calculations ?
There are several useful threads in PPRuNe, eg
wet vs contaminated runway - PPRuNe Forums Take particular note of OverRun's comments. He is an airports design engineer specialist. Unfortunately, you won't be able to quiz him at all as he died several years ago, much to PPRuNe's dismay as we lost an extremely competent and knowledgeable engineer.