how to check if right number of hairs have been transplanted

How to check the number of grafts transplanted? When a air is transplanted, there is a slit left. Can there be multiple hairs in one slit? I am asking so that i can check the number of hairs actually transplanted by counting no. of slits. I am concerned about the number is because one of my friend had an FUT and he felt that no. of hairs transplanted was half of what the surgeon claimed. Please help.