Jagdflieger unconfirmed victories and official confirmation of claims

[Franek Grabowski]

Well, German claims (or rather veirfied victories - there is a difference) were more-less accurate only when the wrecks were counted. That is why kills in Poland, France, Yugoslavia were closer to the actual enemy losses than in the Battle of Britain or in Normandy.
Otherwise, verification of claims was only a morale boosting process and of no other great value but perhaps some assesment of training and armament.