Sure, the breaker has to be able to handle the PFC, which is the higher of the PEFR and PSCC. Under most circumstances, the PSCC will be the higher but, as you've said, if its SWA with armour used as CPC, it's possible that the PEFR could be the higher.
However, I think that this is all pretty academic. This is a DIY forum, hence relates almost exclusively to domestic installations, in which PFCs are pretty modest. It may perhaps be different in other parts of the country, but I cannot recall having personally seen a domestic installation PFC appreciably greater than 1 kA, yet I don't think you'll find breakers that cannot handle 6 kA.