WWSF isn't just floating - it's what % of the flops you see that you win.
So it's going to factor in hands you won @ showdown and hands you won w/o showdown.
Obv the higher the WWSF % is, the more pots are being won without a showdown.
So rather than floats, it's times you are:
1) Betting vs missed cbet
2) Raising cbets
3) Floating and taking away the pot
4) Winning at showdown
It won't reflect whether you had the best hand when you took the pot away and they folded, but obviously the higher WWSF is, the more full of it the player will be, since nobody can make a hand every time.
With all stats, they need to be taken into account the framework of the preflop ranges. For example, a nit who plays 15% of hands pre, will have a lot stronger of a range. So when they see the flop, they'll have a stronger hand and will win more of the time. Conversely, a LAG playing 30% of his hands, cannot hit the flop that much, so they'll be raising and betting with air more often.