Speaking of flowchart completion, at the end of Day 7 of Arc's route, when we chose what to ask Arcueid about, I can't select the "What are the 27 Ancestors?" option neither in my minimized Arcueid flags save file nor in my maximized Arcueid flags one. Is that an option only available on a second playthrough or something like that? I tried a few logical paths but I couldn't find whatever the condition to unlock this choice is.