Dragging up an old post while looking for an answer. Initial qualification is valid for 2 years.
4.2.3.2 Extended Validity. Qualification of a process
may be extended indefinitely provided an auditable
record is maintained from the date of the initial qualification
that verifies that the welder/welding operator has
used the process within a six month period to weld applications
normally welded by the certified individual.
The question is does the 6mos start at the end of the 2 years and extend it for an additional 2 years?