31+ are the challange tiers. You either pug it and run it in one go (or try to), or you get people you can run it in parts over a few days.

Thats the way its designed. I personally dont want it to have it broken into 3-4 tiers. That to me just makes it easier to do, not harder, simply by making it "Oh hey, if we make it to 81, I no longer have to do 31-80 and can just restart at 80 over and over.

Thats stupid and less interesting to me cause it drops the stakes at higher floors cause I know Ill have a 'safety' net. IMO, just leave it as it is. I like it that way. If they add another 100 floors after lvl 100, sure, then create a new tier at that point. But until then, leave it be.