I've seen new hair grow in even after 18 months so it is certainly possible that more will come in the months to follow. Still i think that most of it has probably grown in at this time. Some of the hair has just started to grow. As it continues to grow, the increased length will add more coverage. There is nothing wrong with waiting a full 12 months. I think you are certain that you want more density on the hair line so you probably already recognize that you will need another procedure to reach the density you desire. Therefore, you probably can safely begin scheduling for that. I hope I am wrong and that you will get far more growth soon, however.
Hair line work must be done well in order to create a natural result. If you perform the procedure poorly, you will get an unnatural result. It is far better to have a hairline grow in thin and natural rather than thick and unnatural. Right now you have a thin hairline and need more grafts. Asian hairlines are often much broader than those of western caucasians. Asians prefer to have broad hairlines recreated for them. This was done for you. I do not like grafting on the temple side of the head to bring this frontal-temple border forward on the face. I think it is very difficult to make this look natural. Of course this is my opinion. There are many physicians all over the world who do it all the time. Every physician has his own aesthetic sense. All I can ever do is teach a physician how to perform a transplant well. I cannot make another physician always agree with my opinions regarding aesthetics. Furthermore, many times it is the patient who wants the work done and the patient who tells the physician where to place the grafts. For all I know, you helped design your hairline. I always want my patients input, but if a patient wants me to do something that i do not feel will look natural or good, I will tell the patient and generally I will not do it even if the patient insists. I refer these patients to physicians that will gladly do things that are high risk. Grafting the sides of the head in order to pull the frontal-temple border is a high risk procedure. I don't like to do it, but other physicians will do it and I guess they have a high degree of success with it. Again, this is an individual physician decision that is made with a patient.
The photos you have sent are not ideal and I would like to see more pre-operative photos. I would have a better opinion with better photos and the full story. I think you are in good hands with the clinic in Korea. They got good growth. I don't personally love the hairline design in the temples, but this this is easy to resolve. Alternatively, you may wish to simply add more density and see how it turns out. The main thing is to get a great result that you can be proud of. Trust me, it is far worse to have your hair grow in to the point that it looks like a hair transplant. I don't think you want that. It is always better to be thin and natural in appearance rather than thick and unnatural or pluggy. Also, I've seen far worse yields at other clinics in Korea so there is risk choosing a different physician. I was not there when you scheduled your procedure. It is important for patients to know that anytime you work on a hairline, there is a 50% probability that you will need a second procedure and a 25% probability that you will want a third. There is a 5% probability that you will want more than three procedures to add density on a hairline. Every patient is different in terms of what they expect. I think you should sit down with your physician and discuss you goals and expectations with him. Let him know what you expected and try to resolve the difference. He's a good guy and he will listen to you.