While on this screen for Zenith, my view of the timer was constantly blocked by a string of Sakura Festival prompts. Not sure if this is possible but it would be a good idea to prevent these prompts from popping up, while in Zenith.

Lastly, Zenith should certainly last to 24:00. It is my understanding that the current time slot was allowed because it's the most active time for users, however, it should be obvious that it's only a busy time because of daily events. Zenith battles take so long that it leaves people to have to choose between daily events or weekly battle.