I'm glad someone has pointed out that it isn't a good idea (or legal) to use wet figures on a dry runway. If find myself having this discussion fairly regularly at work, usually because of the misapprehension that going 'wet' is safer whereas the opposite may be the case.
There are some combinations of aircraft type, weight and runway length that give a higher TOW with wet over dry... I think some operators used to 'cheat' a bit on occasions by using wet figures inappropriately.