Where are you getting that from the link that you shared (which is one specific school)? The link you shared shows a figure of $34k and doesn't show a clear breakdown of administrative vs non-administrative costs. The closest I can see in that link is that $13k/$34k is allocated to central services, but most of that cost goes to things like the school buses and the cafeteria and the security guards, which are direct services to students, not administrative overhead. They just are run at the system level, not the individual school level.