Ah, well that explains it. On a side note, would you mind answering me this: "Is sub-15 Hard mode possible?", I'm trying to go for 100% base game before going for challenge runs and I'm stuck on this specific achivement.
Wow, then I'm going to tell you, Hard-mode sub-25 is a challenge all on its own, beating that took me three weeks, you seem like someone that enjoys a challenge, maybe you should try it.