Imagine in an alternet scenario where Nazi Germany was much better prepared for D-Day and the Allied Naval Assult was defeated and driven into the sea. It would take at least several mounts perhaps even a year for the Allies to prepare a new invasion. By then the Soviets would be in more advanced positions. By the time Germany surrenders I think the Soviets could push all the way up to the Rhine. In this scenario I could see the USSR offering to retreat from most of West Germany in return for recognizing some parts of West Germany as part of East Germany. The USSR might want Hamburg and Schlesinger-Holstein or Bavaria. Both of these areas had more Communist supporters than most of OTL East Germany. Of perhapse Stalin just refues to withdraw from the Rhine or only withdraws from small parts of the east bank.