If you do the tests then on clean hair not loaded with products, I am not fully convinced they work.
THE NATURAL HAVEN: Junk Science - Hair Porosity Tests / Float or Sink
I 'diagnosed' mine by my hair's behaviour (dries fast with only rinse out conditioner, slow when loaded with products), the fact it is colour treated and loves coconut oil and protein, the really damaged stuff used to get dye build up but that is mostly cut off now.
Is Deva protein rich? I thought it was more emollients and glycerin, could be wrong tho. Which Deva products?
Does your hair like protein treatments? Or coconut oil soaks on dry hair? Do bear in mind hydrolysed protein does two jobs, penetrates the core and strengths that, patch repairs the surface acting as a film former. Both can be beneficial: just because protein works for you doesn't necessarily mean it is penetrating. Do you have damage, be that colour, UV, mechanical, heat?