Hair typing should be done on unmanipulated hair. Not hair with product or hair that has been brushed out. Manipulated hair can mimic other textures. So the point about brushing out curls is irrelevant.
I do have very small coils in my hair. However, I consider myself a 4b not a 4a because my hair does not have a clearly visible curl pattern. To me this means, that the average person would not look at my hair and call it curly. My hair looks afro-textured even when my very small coils can be seen they still don't look like curly hair. Because the coils are so tiny it looks moreso like a fluffy cloud.