One thing I didn't see much discussion is the mention of Ayane being new to "this line of work" in page 4. At the time of self-doubt whether she fits the escort business, Chiaki appeared and made a series of requests, which is probably part of the reason Ayane feels the affection to Chiaki. For Ayane, Chiaki literally saved her "carrier" (and probably allowed her to put food on the table), while for Chiaki, probably not so much (it seems to Chiaki, Ayane is only a close friend).
Also even though many doujinshi says otherwise, for anyone in the escort business for some time, it's a known taboo to develop affection or relationship with customers. So Ayane's line in page 4 probably also serves to show how she is "inexperienced" in this escort business?
Anyway, Chiaki moves on to her new life, Ayane's heart broken (with many reader's, too). There's only so much a service provider can do, alas. Maybe Ayane will learn the cruel lesson next time someone requested her...
(Don't get me wrong, this piece of work is heartbreaking, I just also found it interesting finding pieces of clue in the work that provide introspection to Namori's thought while creating this)