One of the advantages of a performance based approach to benefits realisation is that it provides a structure for evolutionary delivery.  Project planning becomes focussed around evolving benefits, rather than evolving products, i.e. making small improvements that are useful to people (users), rather than chunking up project deliverables for the convenience of the project plan.  The choice here might seem obvious from a business perspective, but people do struggle with the concept of evolving benefits.

More to follow on this subject.