I don't know of Dr. Khan's work, but I do know that there are many other bad doctors performing outdated plug transplants in countries like Pakistan and India. Please be careful.
Look at the article here called Best_hair_transplant_procedure. You might even print that article out, and bring it with you to your appointments, and ask if the clinic uses this EXACT same procedure. Ask the doctor you are considering if the clinic uses microscopes to dissect the grafts. Microscopes can increase graft yield by a reported 20 to 30 percent. That means that clinics that don't use microscopes may be throwing a percentage of your precious donor supply into the garbage. Make sure that you get microscopically dissected Follicular Unit grafts, and not Minigrafts, which can look pluggy.
Some doctors in India and Pakistan still use big punches to harvest donor hair. This approach should be illegal, in my opinion. Be careful!