Quote from LittleMac:
why no fan of the first dominant traverse and what(in terms of tapes/rules for creating a traverse) qualifies the lateral as a lateral traverse?
Based on Spydertrader's comments, I think the important context is that the first down Traverse had been completed (including not just Pts 1, 2, and 3, but also a Flaw). Only after this did the lateral form. Because the lateral did not form until after the completion of the dominant down Traverse, we view the lateral as a new, non-dominant Traverse.