Deep Dungeon - any good?

[SilkaN]

From what I understand, KOs don't matter. It's as long as your party doesn't wipe, and you have the same fixed party from at least floor 51.

So you're good unless you get a duty failed; then you're going back to floor 51.

I've never bothered with the higher floors so far, but doesn't it say that the KO count needs to be zero?