The big reason for Figure > Symetr's failing is becasue one side, either at the hands or feet, has or has'nt Figure > Inverse Kinematics(IK) toggled on.

For Figure > Symetry to work the IK of the both hads needs to be the same(be it On or Off,) and the same goes for the feet.

alexkuzelicki - FIle > Run Python Script.