Becoming a VP(Admin) is via a different route. VPAs are not education officers (EOs), they are rarely if ever ex-teachers. They usually come from the private sector or other areas of Govt, and are on the MX scheme of service. On average they draw about the same pay as a HOD, but it seems to vary wildly as some are very experienced and can be drawing far more. You will require usually >5 years of management experience, the most valuable kind being those dealing with $$$ and accounts.

KPIs are really typical administrative stuff. The General Office staff, technical staff, OSOs, OM, etc will report directly or indirectly to you. These folks will help you look after day to day operations, but your main area of purview is finance. You will ensure that finance-related procedures are adhered to and the budgets and books are kept in order. Of course, this is a pain in the ass.