I'm a US citizen in who has been in Germany for research since May 31. I applied for my residence permit back in June, but because of how incredibly slow the Munich foreigner's office is, I have only received my Fiktionsbescheinigung and not an actual residence permit.

The Fiktionsbescheinigung was issued under § 81 Abs. 3 Satz 1, which means it is not valid for travel.

I am supposed to go back to the USA for a short visit next week. Will I be denied re-entry to Germany since I have now been in Germany for longer than the usual Schengen 90 days out of 180?

I have found a discussion here (in German) suggesting that citizens of the visa-free countries listed in § 41 Abs. 1 AufenthV (including the US) may re-enter Germany, even if past the Schengen limit. But I can't risk being turned back upon arrival in Germany, especially because my house in the US is being rented out.