In my note above, I wasn't sure if it was a sending error or rolling error, although I suspect it was a sending error. At AAMC this is called a combat declaration error, and you are right. If the battle is to be re-done (no other agreement reached), then it needs to be re-declared and re-rolled completely. If it was the Russian turn, then the game reverts to that point.

While the Axis player "suffers" from this, AAMC takes the view that BOTH players are EQUALLY responsible to ensure EVERY move is accurately done, so whatever penalty he suffers it is at least 50% his own fault.

BW