I think it is possible, but I don't think such drastic changes are solely attributable to changes in skin chemistry, but instead changes in brain chemistry/neurotransmitter balance, and/or changes with regards to yeast/fungal infections, especially chronic mild yeast in the sinus area.
What worries me is that getting 70+ hours from a frag is usually a sign of being *over sensitive* to things, and sounds like some form of MCS (multiple chemical sensitivity). I've suffered MCS in the past and it is very unpleasant in the end. Some fragrances didn't bother me much at all, while others were magnified tenfold, perhaps a hundred fold, in their strength. I remember there was one air freshener my ex had bought, one of those you plug into the wall, and I could smell it 75+ feet and multiple rooms away, very strongly, as if someone had just sprayed a ton of it on my chest, while others could barely smell it in the room it was in!
Have you just found increased longevity, or have things become unpleasant or seem sharper or screechier or cause any kind of discomfort or pain, too?