I feel that porosity is a factor too. I have hair that's between fine and medium but resilient curls. But the curl gets greasy, lanky and undefined (a general mess) if I over condition and I think I OC easily because my hair is porous. Oddly enough it doesn't seem to get weighed down from styling products.
I agree that, for me, curl type isn't that important when using products. In some ways it behaves like 3B and others like 2A.
So many variables