Yes. He extended that scar by scarring new area along the line. That means he created new scars on places that were not scarred before.
If you have a line of 5 meters and you extend it into 9 meters, it means that you created a new line of 4 meters. And you did it by yourself, regardless of whether the person before you created a line of 5 meters or not.
Since you're spam shittalking "Zoro fans" while presenting no argument or rebuttal of your own, at least have the common courtesy to think before you come up with logics such as one above.
I don't try to downplay zoro i just say that yes it was harder to FIGHT while injursd thats obvious, but im talking about that attack, if the injury would affected him so much he would not be able to use the attack as intended, but he still did, with hardening and COC and all that.