For the next several weeks, as the mods are completed, we are only selling 12 in F. Until the mods are completed (or substantially completed), we don't want to run the risk of selling 16 up front and have a plane that only has 12 F seats show up at the gate. As others have stated, if the plane shows up to the gate with 16 F seats, then those additional upgrades can be accomodated at the gate. At some point in October, the seat maps and capacity should reflect the modified F and Y cabins, as the mods are expected to be completed by then.