PMPs are manually intensive, difficult to use systems that cannot look across state lines. They "inspect and correct" transactions AFTER they occur, usually after tens or hundreds of a type occur, before a pattern emerges. They then correct only the most notable/egregious violations. At best their information is days old when used by doctors and pharmacists.
Castlestone works on a simple card-swipe as in a retail store, works across the nation,and works in real-time - documents all prescriptions as they are written, prevents bulk writing, duplicate writing, and, Castlestone prevents filling false prescriptions, INCLUDING cash payment transactions.