2004 API 620
5.26.1 excerpt:
"The UT acceptance criteria provided in Appendix
U are based on fracture mechanics and assume that any flaw may
have crack-like characteristics."
U3.6 addresses TOFD and does not differentiate between other processes except to note the limitations of the process.
Acceptance criteria is based on three tables in 620 based on thickness of the weld, upper bound height, sized height, and length.
I don't have a current 650 but I would be surprised if there is any real difference.
Regards,
Gerald