[Freesurfer] converting .nii.gz label to .label for FS

Hello,

I've derived a .nii.gz atlas-based volume for a specific part of the cortical surface. I've binarized the volume and now I want to convert the file to a .label file that I can use to identify particular vertices in native FS space for that same subject.

This is what I have tried so far:

mri_vol2surf --src mask.nii.gz --srcreg /tmp/reg.dat --surf pial --projfrac 0.5 --hemi lh --out mask.surf.nii.gz

mri_cor2label --i mask.surf.nii.gz --id 1 --l mask.label --surf SUBJ1 lh pial

However when I overlayed the .label onto SUBJ1 the vertices did not match up and was completely off the region of interest on the cortical surface.

Does anyone know how to fix this or how to proceed with conversion differently?

Thank you very much, Kareem