Hello Franck
Actually the details do match my understanding of his career. He first served with 7./JG 52, then was transferred to JGr Ost as an instructor and finally returned to combat duty with 9./JG 52. Please see the short biography that I have compiled using mainly Obermaier as my source.
Dammers.zip
I hope this helps clear up any confusion regarding his career. Any comments or corrections are most welcome.
Horrido!
Leo