I’ve only had one game get this far vs. Amon-Sul. He introduced me to the rule that friendly powers can claim lands, but we played the second half of the game as if you did not have to concede the land to the enemy first before claiming it as income.
In the end it helped him more that we played that way (he was Axis and the situation was very similar to this). The rule helps the Allies since the Axis has more territories it must gain in order to win. This considerably changes how I should have played the last several rounds. I’ll have to stew over this a while before proceeding.