They suffer from low ferritin, which is a bit different.
Uhhhh, I had a link I posted awhile ago, but the gist of it is that the apheresis machines destroy a significant amount of red blood cells in the process of separating your blood solids. This has been shown to have a conservative effect on the stores (ferritin), and also reduces HCT at the same time.
I used to just recommend platelet apheresis, but as new machines are being put into use that limit the destruction of red cells, it's not as viable as a sole means of HCT control.
For those that tend to have high HCT, even with a whole blood donation, it's still worth the time and effort as it does still reduce your HCT by around 0.5-1.0% a donation. I personally do both as I enjoy other facets of AAS use in conjunction with my doctor prescribed TRT.
Mprtz or Tron can probably cover anything I missed.
Edit: The way to tell if it's the older (and better) apheresis machine is by how it does the return and draw. The shitty new ones (supposedly they have a higher yield, they don't) will draw your blood in one arm, and return it through the other. The old ones would just use one arm, and draw/return through cycles.
I really miss the old ones in my area.