Japan 46 Campaign Supply Sources

[Elxaime]

Quick question on the Operation Coronet scenario for Japan 46.  

Playing Japanese side, I've noticed that for the main campaign (600 plus turns) there are no Japanese supply sources in the Boso Peninsula area and thereabouts southeast of Tokyo Bay.  This means that once the peninsula is cut off from Japanese map edge supply sources, any Japanese units there are isolated.  The same is true for the Miura Peninsula on the other side to the southwest of Tokyo Bay (although I don't believe that area is modeled as being Japanese-held in the late campaign like Boso is).  

However in the later campaign scenario, which models some last ditch Japanese units holding the Boso Peninsula, the Japanese have a supply source down there (and hence are not isolated).

Is this inconsistency intended?  It has a significant impact on Japanese strategy in the main campaign if there are no supply sources beyond the map edge ones.

Many thanks in advance.