[Freesurfer] white matter edits

According to the tutorial at http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/WhiteMatterEdits, we should be looking for these holes in the white surface, but when I looked at my processed data using tkmedit SUBJECT brainmask.mgz -aux wm.mgz -surfs, I saw many such holes. They seem to be ubiquitous throughout all 20 of the brains I have processed. Some might be true mistakes in the white matter surface, but I thought maybe some might just be holes that appear because of the shape of sulci moving through 3D space. Or perhaps my Talairach is off? Is there any material that instructs how to tell the difference between holes which need to be fixed and those that don't?

Thank you, Vincent