yea tired was just for descriptive purposes, I have no idea whats going on reallyyeah mine on 20/4, they start to lower there leaves at about 18-19hours on, and get ready for lights out,
but dont let this fool you into thinking the plant is tired, the plant wouldn't do this if its original light schedule was 24/0 as it wouldn't think about rest at all, once its had a few days on a schedule with dark hours, they adapt to that and will prepare for sleep an hour or so before lights off