It doesn't last I checked. It's probably a pain to add as they rely on users to use the addon they have which is in japanese that limits how many that use it. There's frequent times, especially ate evenings/late night EU time where the skywatcher on angler is very slow on updating due to lack of people with the addon checking for it.

Best is always to check a combination of the two if you want to use the timetable page at all. I stopped using the timetable page a while ago tho due to it can sometimes bug out (especially when the page has high traffic) and just use skywatcher+individual fish if I'm uncertain on when they are available.