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/ Transitioning to gray
Cleanse: CJ Daily Fix, JC Cleansing Cream, TJ Tea Tree Condish
Condish: JC Too Shea, CJ Curl Rehab (both as RO & LI)
Stylers: UFD CM, CJ PP, JC Spiralicious, Darcy's Cream Gel & Cocoa bean whip