I have been doing some research regarding scalp hair density. Currently, hair transplant doctors use Haircheck device to observe changes in density as well as caliber in comparison to the donor (control). Most doctors say haircheck numbers should be exactly the same at various points of the scalp for a nonbalding male. After doing some light research, I learned that you are born with a finite amount of hair follicles, and never develop any more hair follicles.
In my theory, and please correct me if I’m wrong, for your hmi number from haircheck to be exactly the same at all points of your scalp, your head would have to grow perfectly symmetrical to the way it was shaped at birth. If your head grows more in length than width, this would create a slight variation of the top of the scalp vs the donor area, as it is stretch further. What are your thoughts? I have to say from reading your blog you seem to be the most down to earth, a straight shooter in the industry.
The Haircheck measurements are a mechanical measurement which is slightly error-prone. I generally take 10% variation of the measurements in consideration as I use the instrument. Still, a 10% error rate is acceptable, but I do believe that hair is uniformly spread around the scalp.