Yep, it's exactly that. The level of planning in this is amazing. The author manipulates the chronology of the flashbacks so perfectly that we can only find out about all the stuff that happened exactly when the author want us to find out, and not even a second before that...They did a similar thing when they cut the scene between Osiris and Seth in chapter 10, showing us the rest of it (of how it ended with Osiris forcefuly kissing Seth after taking off his headpiece) only through a flashback in chapter 32... And it was the same with the two flashbacks in chapter 35: while the first flashback of chapter 35 is exactly the same as what happens in chapter 47, the second fhashback in chapter 35 shows how Seth and Osiris' last conversation ended, after Osiris had asked Seth "Why do you think your wife chose to marry you?": in the 2nd flashback of chapter 35, Osiris gives his own "answer" to that very question.
Just reread chapter 14 and there’s actually a flashback from Horus of what we see in chapter 61. The author’s got some crazy good story planning skills. Makes me excited for S2