"Yes, the displacement Imagemap was plugged into a Subtract node - no clue what that was meant to be doing"

 

was to help Poser. Poser has a very simple way of handling displacement. as in black = zero, white = full. the math node moves the zero point to allow for a greater range of displacement ranges.

Airport security is a burden we must all shoulder. Do your part, and please grope yourself in advance.