Hooray, an update! Nice timing too, with the recent license announcement.
The backstory continues to add to Ami's character. And apparently shamelessness runs in the family; I couldn't imagine being a parent who comes back home just to beg their high school child for money.
The scene at the end is also interesting. I'm getting the impression that this is all some kind of messed up "test" that Ami's putting Rei through. Like she's acting really awful to intentionally try and drive Rei away, and Rei realizes and is calling her on it. Certainly doesn't make what she's doing right or healthy, but it does make for an intriguing story. I also wonder why the friends keep going along with it? Surely they must have some awareness of what's going on between Rei and Ami, and ought to know well enough to politely excuse themselves?