I agree with the layers theory. I have the same issue that my back curls get more weighed down and aren't defined. I wonder if maybe you are not getting enough product into the back. I decided to experiment myself with that and really focus on the back. When I did that I noticed more defined curls. So maybe the next time you add your products pay special attention to that area.
CG, High Porosity, Fine, Low Density, Medium Elasticity
Suave, V05, GF Go clean gel, ACV rinses, CO, and Gelatine PT.