B. The DOT code and/or SOC code assigned to the initial I-140 employment for petitions that have a certified ETA 750A or consider what DOT and/or SOC code is appropriate for the position for an initial I-140 that did not require a certified ETA 750A. Then consider the DOT code and/or SOC code, whichever is appropriate for the new position to make a determination of “same or similar” occupational classification.
http://blog.wenxuecity.com/blogview.php?date=200708&postID=10812#sameOccup