Vapp is reccomended as Vref+ additives for wind (1/2 steady headwing +all gust factor) up to a maximum of Vref+20.
Sops where I have worked then give a stabilised approach criteria of Vapp +10/-5. Theoretically, therefore, if you've used the whole 20kts addititve (say a wind of 20 gusting 30) you are still within stabilised approac criteria at Vapp+10 =Vref +30.