It’s not really US versus German. I think you’re referring to an aggressive entry versus a precision entry. Your description of the German entry is exactly how a precision entry goes. It’s not like the other dude that wrote the book down there described. You never, ever put more people than necessary in the room. You slice the pie like its IDPA and rotate entries with the buddy system. It reduces the risk of funneling and bunching in the situations its required.

Aggro entry is less complicated. Breach, flashbang, three man stack up the left, right, and center blasting full auto with both eyes open. Stay clear of hallways and other doors so you dont die. Its fun as fuck. What happens after the entry is 100% situational. Depends how many stories, how many rooms, how many people you expect to be armed, why you are there etc…