A couple of things to keep in mind: 1) FireFly uses micro-polygon displacement which basically means that every single pixel on the final rendered image becomes a vertex point so a map applied will raise or lower each point accordingly.  2) Cycles/SuperFly only work on the actual Vertex points that are in the mesh, so unless you crank the subdivision level up several times you won't get anywhere close to the same result.  This has always been the case ever since Poser 11 came out.  3) FireFly's displacement maps (based on a Gray Scale Map) have NO displacement with a value of 127, Zero goes in and 255 goes out. So, if you are feeding the Cycles engine with the same map then it starts with the skin already displaced.

When Poser 11 first came out and there were no SuperFly materials making it so the two render engines could basically use the same materials made sense.  However there does come a time when the two are going to become very different and expecting them to keep working and giving the same results with the same setup is counterproductive and holds everything back.  

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13