I do not think the plane to BKK originates from SFO. I flew SFO-NRT-BKK on September 14. We landed at NRT at gate 25 and departed from gate 26. I have taken this flight more than 40 times in the past 3 or 4 years and I do not remember ever departing to BKK from the same gate we arrived at in Tokyo. On the other hand, my return flight on September 22 was the same aircraft from BKK to SFO - with a crew change in NRT.