Fracture control can be complicated enough without the additional subtleties of things other than mainline pipe. It is not surprising that questions arise in this area.
AS2885.info has had a couple of recent additions dealing with Charpy testing for pipeline components – specifically hot tap fittings and flanged valves. These are quite specific issues but may also provide you with some guidance on how to handle other similar topics. And if there are other aspects that are not clear feel free to comment here or email email@example.com.