Mike,
I have no doubt that you are right, since I had no idea a 28M ever existed; or if it did, how they measured it. It was fun to measure and figure out my unit anyway, and I now have a better understanding of the real numbers that I wouldn't have had without spending the time.
And besides that, my conclusion about the "equivalency" conspiracy/mystery is much more intriguing than just saying "add a hypothetical three feet to the open length." Why should I let the facts stand in the way when the arithmetic works so well? On the other hand, if heresy is frowned on, I don't want to be a source of misinformation and can just delete the post and entertain myself with the information gained.
