You may also offer a discount to educational institutions for multiple purchases. If you choose to offer a volume discount for an app, institutions that purchase 20 or more copies of that app in a single order will receive a 50-percent discount.
Your existing Mac apps will not be automatically enrolled in the discount for educational institutions. If you would like to offer your existing Mac apps at a discount for the Educational Volume Purchase Program, check “Discount for Educational Institutions” in the Rights and Pricing section of the Manage Your Apps module on iTunes Connect.
For more information on the volume purchases, hit the link below..