I am not sure which figure (Figure 5.65) you are referring to. Is it in this document: https://www.hark.jp/document/tf/generating_transfer_functions/Generating_a_Transfer_Function_Using_HARKTOOL5.html?
If it is not in the link above, can you please post the link of the documentation which has Figure 6.56? It will help me understand your question better if I can see the diagram.
HARK Support Team