Really sorry about that. I'm working on that now and hope to have a fix in a few days as well as better balance on those bonuses.
(NOTE: just uploaded 1.0.21 which fixes this)
Yea, 300+ lvld are unbalanced, even with lvl 200 and 300 star+ all of perks maxed it takes 1hour+ to kill normal monster, and bosses can be killed only by precious perk
you need have minimum 202 exp to second * 2, 303 exp to second * 3 and so on.. 606 exp = second * 6 and click * 2.