based on multiple reports from other people and what I got after doing it myself, it seems indeed that it just says that when you pass the third scheme, independently of how many attempts you've made (I know for a fact I took fewer attempts to solve the whole thing today than I took to solve the first scheme the first time, since I could just reuse solutions for the first two and brute-forced the third one elsewhere)

incidentally, the crosspost of this post became unusually-for-me popular on tumblr.