it seems that you are mixing different information source here. Your 3/21 comes obviously from the seat map and this a very unreliable indication on the actual bookings in W. The other figures you posted (W6 S6 A6) shows that there are only 6 seats bookable in PE, so this is rather indicating relatively solid bookings. Add to that Eco which seems to be well booked too : the numbers you post, in my experience, indicates an an almost full Y cabin (so overflow to W may happen). J cabin seems to be wide open.