I'm not sure I understand the pricing policy. If I had bought V0.2.1 (4$) and V0.3 (9,10$) I would be at 13,10$. V0.4 then costs even more? And each additional version and I have to pay the full price? And I have to live with the fact that the game might never be released!
If I were you, I would think again about this pricing policy, especially since the Early Access for 20$ was mentioned. I would actually be there immediately. I would also pay 30$ Early Access for an indie game. But certainly not 7 or more versions with 9$ and more each without knowing if the game will ever be finished. I won't pay more than 50$ for a full-price game either.
So, count me in for the Early Access, but with this pricing policy not earlier.