I’ve recently been reading Maigo ni Natteita Youjo wo Tasuketara, Otonari ni Sumu Bishoujo Ryuugakusei ga Ie ni Asobi ni Kuru you ni natta Ken ni tsuite (aka About the Time I Helped Find a Beautiful Exchange Student’s Lost Little Sister) and it’s quite good too, but yeah - this one somehow really nails that whole dynamic.