I would not be sooooooo sure. There are many, many examples of what the British would call "Immediate awards" ie. then and there for an action, or soon after.... and there are many examples of awards for accumulative actions. Most post war ones seem to have been for accumulative actions over a longer period. I have a number of post war awards where the division fought extremely heavily 1916-17 and first couple of months in 1918... then twiddeled its thumbs for the next half a year (plenty of time to make an award then) and the guy finally getting his award long after the war for no specific action, but because of an accumulation of good service from throughout the war. Damned nice group it is :-)