This is interesting..
The chapter reveals that normally you wouldn’t be able to re-attempt any boss floor, except if the boss floor has a sub quest that is still unexplored, and once the sub quest is fulfilled then it will be closed forever and no one can attempt it again.
This would explain why usually all newly formed parties are missing the experience for real dangerous situations such as boss floors. I always assumed that the master can resend any party to any floor, including boss floors. Also, it would explain why NPCs found in boss floors such as Priasis would still only know about Hans party and no other party.
