The twist threw me for a loop, but damn, grandma is great. Best yuri manga grandma I've seen in a long time, lol
But that aside, that last page. The panels seemed to hint at something in the general vicinity of drama coming up soon. The panel with the "house to myself," bit looked a lot like the landlady had some kind of realization that goes beyond the rest of the page. That may be stylistic, but the next panel lends itself to such a setup as well. Asako says she's joking, but it's mostly off-panel and focused on the floor, like the mangaka wanted to hide her face. And this may be a translation thing, but the comment "joking, just joking," seems a little too composed to me, but that might be reaching. But the "joke" itself also didn't really have the feel of a joke, either, in how she said it and in the fact it didn't show her face either.
I dunno, maybe I'm just overanalyzing it, but it seems to me like there might be some implications for future chapters.