Your hypothesis is that during the continuation war Finnish fighter pilots under-claimed enemy aircraft destroyed because they were afraid of Soviet retribution after the war?
I think on the face of it that doesn't make much sense but it doesn't mean you're necessarily wrong--it would just be a very odd phenomenon. Especially since other Axis fighter pilots continued to over claim combat results at typical rates up to the end of the conflict. It seems to me that any anxiety about post-war retribution would be based more generally on one's status as an officer in the Finnish Air Force, not on how many Soviet aircraft he reported destroyed on this or that sortie.
Actually, I should clarify that: I do think you're necessarily wrong about that being a widespread pattern, since it appears to be a basic fact that on the whole Finnish fighter pilots (like all WW2 fighter pilots) over claimed enemy aircraft destroyed by a significant margin. But whether it ever occurred in any one instance? I'm theoretically open to it. I'd just need to see some evidence.