I can't afford to do more than look very quickly, so I'll pass this over to felis. But my very quick look tells me that Frau von Knyphausen aquired the property from none other than the von Blaspiels, aka Manteuffel's recently locked up in Spandau and then released and exiled mistress and spy Frau von Blaspiel and her husband the fired Minister of War (whose job now was held by Herr von Knyphausen).

Also didn't Felis original discovery say that the "Frau von Knyphausen's house" description at some point disappears from the address as given in the Adress book? Which might go with her selling the property. To the owner of the porcelain factory that would later become KPM, I see. Anyway, tentative suggestion - Peter kept the address in a kind of work office capacity and had his mail going there?