I have not bothered to read the expansive list of responses to this post. However, that said, I have always enjoyed the discrepancies of size believing they add a touch more realism to the craft. Many is the change of command and retirement ceremony, I participated in, where troops lined up from tallest to smallest behind the squad leaders to form the platoon. People are different sizes and piecing these slightly different scales together merely reflects that.
To quote from BLACK ADDER GOES FORTH, "King and Country would have us believe that all British soldiers are strapping 6 footers with muscles the size of Bormoth." (my apologies to those across the pond if misspelled) And the Germans never obtained divisions of their 6 foot, blond haired, blue eyed, ideal soldiers.