In your example there would probably be little difference, but that is not what often happens in the real world. What happens in the real word "effort" when horses are making their moves. Sometimes it lasts for less than 2 furlongs, but if you have been going to the races for years it is easy to tell when a horse is working hard to get, improve, or maintain position and when it is not. Pace is best measured using both fractions and visual skills because pace figures alone are 10 times more difficult to be totally accurate with than final time.