Not sure that's a SCHSL rule, per se...I've been places where the clock counted up. Doesn't bother me either way...40 minutes is 40 minutes whichever way you count, the officials still keep overage time on the field, and when you're counting down to zero, not even the soccer-inexperienced have to wonder about how much time is left in the half, especially since people have to transition between 45-minute club halves and 40-minute high school halves.
