J'm not an East-Front Specialist, but every day at 17:00 AFAIK at regimental Level, at 19:00 the repport had to be sent to division, the division to corps, and then corps to air armies and etc...To check a pilots claims by checking the opponents losses you need accurate DAILY accounts.
I can see that the Soviets would need to know how many they were losing to replace them, but just how often would they need to report this information ?
Note that there are no "lost" mentions in soviet reports, only "write-offs", for pilots and planes.
DAILY accounts are generaly inflated compared to "compilated loss records" established later, cause the same plane and pilot could "daily" be "written-off" for many different times. In general case "did not return", but recovered later.
There are famous examples of a soviet pilot (i don't remember the name) from the 12th IAP that was "lost" or "written-off" for 5 times in russian archives, even "died" two times in a burning plane. He was still living in 1997!
That kind of exemples are numerous, so i don't thinkany secund that archives were rewritten, in such a "brothel".