When the NBIC was revised in 2001 to reflect the change in allowable stress values in the ASME B&PV code, this created a real hornets nest regarding repair/alteration activities especially for in-service, vessel re-ratings. As it turns out, the committee finally moved forward with permitting the use of higher allowable stresses to re-rate a pressure retaining item when it added RC-3024 , and RD-3010, paragraphs a)-f).
Keep in mind that the NBIC, like any other ANSI Standard, is intended to provide general technical guidance for Inspectors, Users and Jurisdictions. As with any Code, all scenarios cannot be accounted for, and this is where the Jurisdictions or Insurance Agencies have to step in and provided specific guidance. I have no problem using API 579 FFS to assure continued operation or even to support a re-rate. Component re-ratings need to be justified by adequate engineering calculation, that in my opinion (not the NBIC main committee) could include API 579 plus other technically sound approaches.
Since Jurisdictions are like small governing bodies, they can be all over the place on this very issue. If you would really like to know how many Jurisdictions have approved vessel re-rates, I would suggest contacting Mr. Robert Ferrell at the National Board. His number is 614-888-8320 X240.