Jaw surgery vs genioplasty - I'm not sure if a slight overbite justifies an expensive surgery for minimal increase?

 As long as your teeth fit together very well, then jaw surgery may not be necessary. Jaw surgery is performed by an oral surgeon in a hospital setting under general anesthesia with an overnight stay and is very invasive. A chin implant is placed under local and a seizure and takes approximately 30 minutes.  A chin implant only augments the chin forward for cosmetic purposes, and has no bearing on how the teeth fit together. For more information  and many before-and-after chin implant examples, please see the link and the video below

Hello from View Plastic Surgery in Korea.
Receding chin can be corrected either genioplasty or chin implant. Genioplasty is a bigger surgery that requires an osteotomy. Chin implant is rather a simple implant grafting procedure that can be done in less than 30 minutes. Both has advantages and disadvantages. Please consult with your plastic surgeon.
Regards,

The biggest indication on whether you need a larger jaw surgery vs. a sliding genioplasty is the position of your teeth. This is typically evaluated by an orthodontist to determine if optimal dental occlusion can be obtained with orthodontics or if the bone needs to be moved. A dental x-ray can also be useful to your surgeon to help determine which procedure you are a candidate for. Unless the teeth are significantly affected, most people can be adequately treated with a sliding genioplasty. In doing so, your surgeon will be allowed to move you up to 12mm forward. A simple set of facial measurements can be taken in the office to determine exactly how much anterior projection and vertical change is needed to give you optimal facial balance.