Perhaps you misunderstood; they have to take enough hair follicles that fit the radius of a needle head, which they will then clone. After that, someone will have to transplant those cloned hair follicles back into your head, whether it be a surgeon or an automated device (which they hope to develop somewhere down the line). They also talked about cloning more hair follicles than necessary, so that you could store an excess of hair follicles in a biobank for future use. Having had one or four hair transplants makes no difference, they could simply take a couple of the transplanted DHT-resistant donor hairs on your scalp instead. Even then, you will certainly have enough donor hairs on the back of your head despite many previous hair transplants. There's not a single hair transplant patient in the world who can't get his hair cloned.