So after 12 coats of tan, the coverage is "good, not great." There are still visible areas where the coloration is inconsistent. This is a good demonstration of what goes into a very smooth paint job; I certainly don't have the patience to paint entire models like this for gameplay. I think the misnomer here is thinking of each of these steps as "coats" like painting a wall would get coats. When you are painting with very thin coats, one area is drying rapidly while you are working on an adjacent area. I took pains here to go over each area only once between photos. In practice I would be going back to the areas that had incomplete coverage almost immediately after finishing a nearly area. The paint should be thin enough that it dries pretty much as you watch.
I might repeat this exercise with a foundation paint over black primer and see if the result is significantly different.