The hair float test is notoriously unreliable. But, yes, coloring does affect porosity, and it is possible to have more than one type of hair on your head. New growth, for example, is different from damaged old growth.
2C/ Coarse/ Normal porosity/ SW Florida/ Salt & Pepper
Cleanse: AIA cowash, TJ Tea Tree Condish
Condish: JC Too Shea, Tresemme Botanique
Stylers: flax/okra gel or KCCC + CJ PP or JC Spiralicious
Experimenting with Got2B Ultra gel and loving it so far!