That is not a lot of material…and 30cm of thin suture is nowhere near the same amount of material in even the smallest pieces of mesh that are used in hernia repair, never mind the pieces that are used to cover a larger area when deemed appropriate.
Also, are you considering only the incision or the total length of suture used to complete the repair? I honestly have no idea, but are you sure that Dr. Kang only uses 7cm of sutures in total?
In any case, it is not appropriate to evaluate and compare the quality of repairs on the basis of suture length…you evaluate quality (at least from a patient perspective) on the basis of outcomes. So unless there is solid evidence that suggests ‘more suture material = more post-op complications’, then there is probably not a good reason to worry about such differences.