BTW the only thing I am now sad about is we never get to see their dating arc, college arc, marriage arc etc. you know after they start dating and before the daughter grew up.
It was intentionally planned to only be one volume. Inaba had mentioned a while back before its release that it would be a one volume special spin-off to cap off the Takagi series.
Oh, was it? I had a feeling that the story was axed intentionally, given that nothing really happened in there between Chi and her to-be-boyfriend, and their dynamics... haven't really mirrored that of our sweet Chi's parents. Honestly, it looked like a not really good thought out oneshot.