We consider the definition of the Expedited Forwarding Per-Hop Behaviour (EF PHB) as given in RFC 2598\ \cite{rfc2598}, and its impact on worst case end-to-end delay jitter. On one hand, the definition in RFC 2598 can be used to predict extremely low end-to-end delay jitter, independent of the network scale. On the other hand, we find that the worst case delay jitter can be made arbitrarily large, while each flow traverses at most a specified number of hops, if we allow networks to become arbitrarily large