Oh I remember that part. Chigusa misunderstood the reason of Shana being with Yuji (you find your son on the backyard arguing with a girl while sitted right under the window, I don't blame her lol) It was really nice to see how she dealed with Shana, even when she was a complete stranger.
The manga got a lot of original plot, as for what I know, Hooves told me that much of the events there are missing in the novel and anime as well. I think it makes it more interesting, as you don't know in which order they will present the story
