I'm delighted and refreshed by your naive hope, murph, as it points to my pet peeve.
The exacta, according to the rules, is determined by the win/place finishers. Yet the exacta pays off on the win/show horse when it finishes, e.g., 1/1A/2. What the ?? Either the entrymate should be disregarded for the place payoffs, or the exacta should pay off on 1/1. It won't blow up the system to install a 1/1 key, a 2/2 key, et cetera. More betting interests.
But as it stands, the exacta can be win horse/show horse or, in the case of D. W. Lukas in the old days, win horse/way-out-of-the-money horse.