It still is. I'm guessing what they mean is there were enough changes done to the YF-24 design that they gave it a new number, VF-25. Likewise, there's enough changes done to Galaxy's development of the YF-24 that they gave it a new number, VF-27. The YF-24 probably doesn't incorporate the number of changes that the VF-25 and VF-27 made on the design.