Simplify the following text for a Grade 6 native English-speaking person.
Original: Following German complaints that reparations payments under the Dawes Plan were too high , the Young Plan of 1928 , under which the Germans were to pay annuities of various amounts , but none to be higher than two and a quarter billion until 1988 .
Simplified: The Germans complained further that payments under the Dawes Plan were too high , the Young Plan of 1928 was set up and the Germans were not required to pay higher than 2.5 billion until 1988 .