I think I may have found a bug......
Scenario:
default Category (17)
-->CATEGORY-A (9) (displays iphone format properly even with 2 col design)
------>SubCategory1 (1) (does not display 2 col design in iphone format)
------>Subcategory2 (1) (ditto)
------>Subcategory3 (1) (ditto)
etc
------>Subcategory9 (1) (ditto)
-->CATEGORY-B (8) (iphone does not display 2 col design properly in iphone format)
-->CATEGORY-C (0) (ditto)
-->CATEGORY-D (0) (ditto)
It seem as though any category that has no subcategory will not display itself in iphone format if the category design is other than single column or blank format.
Can be seen here 352processserver.com on android.