[Freesurfer] mean thickness

Dear Freesurfer team,

Forgive me if this is a foolish question...

I wanted to overlook cortical thickness, area and volume measures in Gnumeric file after recon-all (checking edits made). However, for several subjects I noticed that the values of mean thickness (final column) were calculated wrong, whereas this is not the case for their independent cortical thickness values. For instance, this happened to subject A09. I'm including the excel file to show the example. In the gnumeric file the number for this subject was depicted as 2/4964 instead of 2.4 etc.. What could have went wrong?

Thank you for your answer in advance.

Kind regards, Caroline