I dunno if there is a mistake in the table of content in this online version but I cannot see it has any extra chapters
https://books.shueisha.co.jp/reader/main.php?cid=9784088914589
Edit: I checked bookwalker and there it is included...
Can you add this promo picture? https://i.pximg.net/img-original/img/2020/01/17/19/32/53/78947487_p1.jpg
They have just been added to many other scanlations
Can you add this promo picture? https://i.pximg.net/img-original/img/2019/12/31/10/20/28/78598879_p14.jpg
They have just been added to many other scanlations
Well I dunno which way to spell her name correctly but I have just seen it as Ootomo pretty much everywhere else
https://kaguyasama-wa-kokurasetai.fandom.com/wiki/Kyoko_Ootomo