Great, we all obviously think in the same way. However according to our captain they consider unusable fuel as part of ZFW, then they put into FMS block fuel manualy but it is not block fuel as we all understand that but it is just fuel for mission. So it looks like FOB is not block fuel here. Even though they call it block fuel. And it works only for small Airbus fleet because B777 crews clearly do not like that.