Tapered Members

Section 5.20.3 states that "f1 (Depth of section at start node) should always be greater than f3 (Depth of section at end node)."  In the model I am working in, it makes more sense for me to define my members from left to right which results in some tapered members meeting this requirement and some do not.

Does anyone know of the reason for this? 

Will my analysis results be affected if I sed the depth at the start to be less than the depth at the end?