All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The principal should follow the methodology applied by the Ministry of Education in this regard. He isn`t allowed to steer the discounts in the direction that he wants if he doesn`t have the authority to do so.
This is because public money is the trust and responsibility of those in charge of it and they must fear Allah when it comes to preserving it and dealing with it in accordance with the official instructions. And Allah The Almighty Knows Best.