I use the file "lh/rh.aparc.annot" and a splitfile as the inputs of the command "mris_divide_parcellation" in order to have a parcellation with more regions.

Now I have a question: for example if in my splitfile I write 4 in front of the region "precuneus", how does it divide this region into 4 subregions? Is it based on a specific pattern or it is random? I mean if I repeat this command line 100 times with the same splitfile, will the results be the same? I would be grateful if you could help me.