I remember wondering the same thing until I was watching 320 simpilot
I know “pre 1.3/4 update” you had to wait till the aircraft decelerate to the first indicator and when the co-pilot announced “flaps 18” you had to click that flip chart in the landing option and do it each time you you got an announcement and actioned it… i.e “gear down” (you put your gear down then click the flip chart and the little bugs moved…)…
Now after the update, you don’t need to do it anymore, you have to click an actual flap option and it sets them all