im not familiar w the terminology of the FBCO
but in the CSO I get super crispy CkThigh Skin , nicely browned
and much better over all that baking in a non-steam oven
there were little bubbles on the CkTh skin , like a very tasty crispy Ckskin cracker.
its outstanding in a CSO
P.S.: I looked at your time and temp
try steam bake 350 - 375 for longer : 45 min ?
keeping an eye on the CkTh's