Well I suppose the sender that "had to be used," for whatever reason that might be, went from no resistance to high resistance, or
vice versa, which was the opposite from what the gauge wanted and it made the gauge run backwards. So Bayer made the decision to just flip the E and F.
That's one of the stranger Cobra trivia tidbits that I have heard in a long while. Most people would have just whipped up a little circuit board, with a transistor, to flip it around the other way. In fact, ERA does just that to get the wipers to park properly when you turn off the switch.