How long will it take for transplanted body hair on head to grow?

I got 600 grafts transplanted from chest to head exactly six months ago. I can only see less than 10 hairs taken from body has grown. At the same time I had got 3800 grafts from sides and back of head. I see around 15 to 20% growth from that area. Will it normally take more time for body hair to grow. I still look like norwood level 5 to 6 bald and I am interested in having body hair transplants in future because I only have donor body hairs left to transplant.