Yes they do cut along the same scar. They actually take the scar tissue out as trying to heal old scar to old scar doesn't heal as well as healthy skin. Its the same with the uterus scar also. They take the old scar out (usually only a few mils of tissue) that is why they suggest you don't have more then 4 C/S as every one you have after the first the uterus is getting that tiny bit smaller. Obviously this is not a problem the first few times but after multiple C/S you can imagine the decreased size of the uterus and thats why your at greater risks of prem labour/placental insufficency and rupured uterus when you have more then 4 C/S. In saying this I have seen women have more then 4 C/S and have minimal complications.