Yeah, this piece calls for a few of the notes in the piano to be tuned down a quarter tone (I forget which ones, it's been a while since I've looked at the score), which explains that. I've never been a big fan of this one, as far as the "most difficult piano pieces ever according to skepto" go. I find it a bit aimless. Perhaps it would do better in it's version for 2 pianos (there are many parts in the score with "optional" notes that are for a second pianist. I don't think this other version has been recorded though.