When you load a NIfTI image onto a mesh, Surfice assumes they have the same spatial mapping. The FreeSurfer inflated images no longer have any correspondence to MNI space. Indeed, the inflated left and right hemisphere are no longer left or right (each is dilated so the X-coordinates extend both left and right of the origin. You will need to use a FreeSurfer too to help you:
  https://imaging.mrc-cbu.cam.ac.uk/meg/AnalyzingData/MNE_SPM2Freesurfer