I can fairly easily comb the part of my hair that's straight... but once I get to the ends of the hairs on the top layer, it will turn into frizz and is hard to comb through.
I think this is just natural for your hair type
I have naturally wavy/curly hair to my shoulders. The hair at the top of my head is mostly flat and straight from the weight of the rest of the hair. I too have curls at the ends and that is where the worst of the tangles can happen. I also have more curls under the top, exterior layer because the under layers do not get as much brushing. It sounds like you have pretty typical naturally wavy hair.
MEK
P.S. The tubes can be called spirals or ringlets.