I believe I stated my source in the post you're quoting.
Krivosheyev? Ok, I understood that was for the Soviet losses alone.
I've read a slightly different story. For example during a period in the Kursk battle (5.7 -8.7 1943) Soviets reported 566 aircraft lost while Germans claimed that they destroyed 923 Soviet aircraft. Thus over claiming by 38,7%
based on the Soviet loss reports. I'm not claiming this to be the absolute truth either. During the research of Finnish aerial victories it was found that there were clear gaps in the Soviet loss records on certain time periods especially on the Northern part of the front (where JG 5 operated). So it could well be that these gaps existed on other parts of the front as well where Germans were solely operating.
Sources:
POHJOINEN ILMASOTA (NORTHERN AIRWAR) by Hannu Valtonen
SUOMEN ILMAVOIMIEN HISTORIA 26 FINNISH AIR FORCE HISTORY: Aerial Victories part 1 by Keskinen & Stenman
Blindly comparing some total loss/victory figures together like that won't yield any accurate results. I guess I need to obtain the book from the author you mentioned and see how the figures are handled in that book and what conclusions exactly the author makes.
All nations, including the Germans, overclaimed, some more, some less.
http://en.wikipedia.org/wiki/Confirmation_and_overclaiming_of_aerial_victories_during_World_War_II