Speed sense on the A1

On the A1 direction Bremen there are five (!!!) different speed limits! And that at just three kilometers! Are you still going? Shortly after the exit Posthausen it starts at 100 km/h. About 900 meters further are 120 km/h. After 400 meters then you are slowed down to 100 and then after another kilometer to 80 km/h. What is the nonsense? Is this only on the A1 so or do you know even more roads in Germany, where such confused signs appear???