In looking at the final state of the front lines in Germany in May 1945, one notices that American forces held about 30% of the territory that would become East Germany, including the cities of Leipzig, Halle, Weimar all of Thuringia, much of Anhalt and the westernmost part of Saxony. Had Truman decided to hold onto these areas, which apparently Churchill was suggesting he do, the implications are interesting. The US evacuated Leipzig on July 2, 1945.
Soviet countermeasures would likely be to not allow the Western Allies any part of Berlin, and perhaps to set up a Communist East Austria. Also, would the Soviets then want to take some land slated to go to Poland in Pommerania/Silesia and put it back in their Germany zone to make for a bigger Communist zone, and make up for their loss of this territory to the US?
I wonder if they would go back to the Oder as the border all the way to Breslau perhaps, and thus the Soviet zone would incorporate maybe half of Silesia?