In my experience it's never that small. You tend to really notice it with vowels, *especially the letter "e" (uppercase or lowercase). When you have lines of text, the error tends to become skewed by the commonly used letters (T, S, R, L, and E). I've *seen* it in trying to reproduce fonts. It's extremely difficult work, not something the Monotype could have done by accident when creating the font in our word processors. Also, as I mentioned in my previous argment, typewriters would have varied a little bit, maybe only in fractions of a point, but the effect would have been visible. Monotype would have had to base the curent MSWord font on this particular typewriter and font ball. Another one would have given them different character spacings.
Letter frequences is a strong point (there must be a systemic difference then). I have to conceede you win the argument :-)