Sliding Genioplasty to help with lip incompetence

[Confusedguy]

I have gotten lip incompetence as a result of orthodontic work, now my chin is down and back and the lower third height has increased significantly so my lower lip hangs low at rest and shows my lower incisors quite significantly. Since I don't have any significant bite issues as they have been compensated by orthodontic work I am reluctant to have a full blown bi-jaw surgery.

I live in India and have located a surgeon who performs sg's quite frequently but I have two major doubts and if someone could help me with them,  it would mean a lot.

1. Will it help my case, I have attached photos below.
2. Is the surgeon's technique proper, I have heard that sg's require bone grafts from time to time and he seems to be leaving a gap between the cut and the advanced chin portion. I am worried if such gaps fill up on their own with natural bone with time. I have posted a video link below of the surgeon performing the procedure.
https://youtu.be/mIfyYGyhgng

[Confusedguy]

One last attachment.

[kavan]

If your chin is down and back and height has increased in the process, then the surgery for that is a sliding genio which advances forward over a diagonal cut in direction of out and up.
SGs don't require bone grafts because the cut segment makes contact. I don't need to watch the video to tell you that.