The response before was that people specifically want to spend 3 turns (or is it 4? the people that care probably know) before changing it. Even if a setting was added, most people wouldn't know about it without asking. I expect that it's possible to make everyone happy (accurate tracking of turns spent there this ascension, only show the warning once after enough turns have been spent there), but does that lead to people wanting accurate tracking of turns spent in every zone? There are a lot of areas where I care about that tracking more than I do in the boss bat's lair.
It doesn't really matter to me what happens there, so I won't be messing with the status quo.