[Freesurfer] Left right flip surfaces

Hello Freesurfer Experts,

I processed all of my brains through freesurfer 6.0 dev for Linux and warped the surfaces to standardized space. For a handful of subjects I want to perform a left right flip of the cortical thickness files (standardized space) for a group analysis. What is the best way to perform this in freesurfer? I have found a previous post referencing mris_reverse but there was a mention of it being off by a voxel when flipped. I wanted to see if this is still a concern with the latest version?

Is there a better way to achieve this goal without rerunning all of freesurfer such as a newer took, or is this the preferred method?

Thanks, Ajay