I created the FS average subject of the same dataset with 5th and 6th order icosahedron tesselation using the following commands:
make_average_subject --fsgd fsgd.txt --ico 5 --out avg_subject_ico5
make_average_subject --fsgd fsgd.txt --ico 6 --out avg_subject_ico6

When I load the inflated surface of the avg_subject_ico5 with tksurfer , it has a oval shape while when I load the avg_subject_ico6 it seems to be a normal shape.
Please, see attached image.

Thank you in advance.

Best wishes,
Marina.