Jeldon,
This is my interpretation as combination of processes is not as clearly spelt out in API 1104 as it is in ASME IX.
9.5 mm WT gives you a qualification range of 4.8 mm to 19.1 mm as per 6.2.2 (e).
Unlike ASME you cannot use the processes separately unless you have performed two separate qualification tests as per 6.2.2 (a)
2. A change in the combination of welding processes,
unless the welder has qualified on separate qualification
tests, using each of the welding processes that are to be
used for the combination of welding processes.
Regards,
DD