Short answer: no. The expenses of a child which child support is intended to cover don't stop when the child goes to school. Does custodial parent's landlord not charge rent for that time? Does custodial parent's car insurer only charge for time child is actually in the car? Nice try, but no.
I agree. That time is usually credited to the parent who has the child within their care, custody, and control at the time despite the fact that they are not physically with the child for those hours.