Those are very curious marks.
It could be something only used by that group, one commander's way of wanting things done by his people.
I agree they look like tally marks of some kind, almost Myan.
Maybe 2 tests taken, 2 tests passed. 3 tests taken, 3 passed.
Great question. And thanks for stating which page to view, 60 is a lot :) I can't believe you found such detailed and extensive records.
Have a great day!