Funny bug: when you repeat quest Extermination, you can go beyond level 70.
You mean Main Adventure Battle 70? Yeah, I can see 71-75 now and can go back but need Extermination to return. And can use Extermination to get to 76-80 too. And there's basically where I'd have to stop. With a really good encounter, I could probably beat 76, but that's taking a while.
But did it. Had a cluster of 4? Flowers and ~2 Mushrooms.