Sure. And there would also be another 25 million Germans living in Pomerania and Silesia. Should these also be counted?
Your point would seem that Poland had a net gain after the war at Germany expense in both in territory and or population ...
Yet the reality is Poland had a net loss of territory of 30,000 square miles and it's population "permanently" reduced by the German policy to create German "living space"... also note that Poland did not gain the German population of Pomerania and Silesia as the Soviet Union forcibly moved them inside the new postwar German border
An in the scheme of things forcible population relocation beats forcible population reduction ... as the dead don't vote (there not Dems) or reproduce...so it does effect relative power in the new EU...
Poland main gripe is as legitimate an small population state's in the US with the added factor that it was one of there New Co-EU states that thinned out there potential Polish EU voting power ...
If Texas invaded Arkansan, after the dust settled Arkansan would at the very least, be pissy, probably for quite a few years, about having less Congressmen in the house and less political clout, money, etc. at the Federal level because of a forcible reduced population by some one they are now being asked to share population proportional voting power with in that same Federal government
Considering most Americans would be able to spell Arkansas, guessing that you aren't American. Apologies if that isn't the case.