Hmm, why draw the line artificially at the Psm and Abhidhamma? What about the Classical Mahaviharins who insist that the Vsm and the Commentaries and Tikas should also be included in received Theravada? What about the other camp who argues that "Theravada" is simply a Vinaya ordination lineage, and not a doctrinal one?
I shudder to think that Ajahn Chah and Ven Nanananda have fallen between the cracks, based on this definition. The definition is not without its utility, but I think it only functions as such as an academic comparison between the different Schools. The Mahavihara position may well be taken to be one vein of Theravada, as I don't see the label as being anything more than a convenient identifier for people who prefer to work with the Pali Canon, or the parts of the Pali Canon they deem to have soteriological value.