Besides the answer from Airbus.I'm not very happy arming the apch at the final altitude.In fact the workload is higher and I can't see any benefit doing it like this.I really think the pilot from Airbus who answered didn't fully understand the question as the wording at the question wasn't perfect (they used "active" instead of "armed" or "engaged". In fact if you arm at IAF (APP NAV)you are still responsible for the vertical navigation (you can take over if not happy) and final mode is "armed" so the vertical/lateral navigation (FINAL APP) will engage at the FAF if all the conditions are met.So I don't really understand this recommendation.Another thing that makes me feel that is wrong is that is not written anywhere (FCOM, FCTM, AIRBUS instructors media..etc).That is the reason I wanna know the certification document for APV approch with ABAS+ Baro VNAV (A320, A330, etc) with LNAV/VNAV minima