What is the ruling regarding conditional precision in shooting contests?

Primary text

If contestants stipulate that the score is determined by hitting a specific location on the target, where a closer hit by one cancels a farther hit by the other, and this results in one leading by the agreed-upon measure, that contestant is the winner. This is considered a type of Muhata. If one hits a location one span away from the target while the other is less than a span away, the farther hit is nullified. If the first hits the target itself, the second's hit is nullified unless the second hits the circle within the target, in which case the first is not nullified, as the entire target is a valid hitting area unless explicitly stipulated otherwise.