Hello Jens,
I believe the following link leading to Pawel Burchardīs excellent site devoted to aerial operations during the Kursk battle will be useful to you:
http://www.lesbutler.ip3.co.uk/tony/pawel/index.html
You can find out that the losses of JG 3 on 5 July 1943 were definitely higher than just 3 Bf 109s.
Hope this helps a little,
Ota