I didn’t mention anything about Ehrlau. I mentioned Mattersdorf. Define what is “Minhag Oberland” and who follows this “Minhag Oberland” that you refer to. Because most actual Oberlander Yidden today don’t.
And the Oberlander havara is very close to the Chasidishe havara. Certainly much closer to the Chasidishe havara than to the Litvishe or the Yekkishe havara.
What gave you this idea that Minhag Oberland is similar to Minhag Yekke? There is a reason that the Oberlanders became very close to the Chasidim and adopted very many of their minhagim.