Joseph…………..
My maternal side is Yekke, arriving in NY from Bavaria in 1868
I was raised that if you are not 20 minutes early you are late.
You arrive for an 8PM invitation at 7:40 and park the car. At 7:57, you exit the car, check to make sure your clothing, hair, etc. are all correctly straight, hostess gift in hand, you walk to the front door and at exactly 8PM you ring the bell.
Someone who is habitually late is not a Yekke, he is an aberration.