I really think the ponytail test as a measure of density is somewhat misleading. A person with coarse hair is going to measure higher than someone with the same "density" (that is, hairs per square inch) but finer hairs. I think it can be useful to measure against hair loss in any given individual, but as a matter of comparison it's not very accurate. It's also very difficult to measure in exactly the same way every single time, so measurements can vary. That said, mine is 5", give or take a bit.
3a/b, F, normal porosity

Suave conditioner, LAL gel