The move away from the construction of complete wall frames and complete cross frames (bents) would appear to be a simplification of the long established timber framing tradition where continuous wall plates were employed.
It is somewhat akin to todays move towards adopting modularisation and as such it represents a simplification or debasing of the earlier and more precise building method and traditions. The interrupted wall plate is certainly not in wide spread evidence in England though that is not to say that it does not exist hence in general I do not think that this style of framing has English roots but much more likely to be a product of Yankee inventiveness.
Your topic and items raised therein are of major importance in helping to determine and understand the evolutionary pattern of framing styles employed in New England.
Hard evidence for the date ranges that you suggest would be important in order to establish stylistic precedence in this region.
