I've not noticed the correlation, but many times I can feel that the carpet is damp but I can't get any moisture transfer to my hand. Whether thats the O2 rinse or the efficiency of the system, hard to tell.
I'm not going to knock it.
I did notice a softer hand to the carpet.
A friend uses Fibre Rinse, and he also only has 2" hose on his Cleanco , no 2.5". We have the same blower, 4.7, he has more horsepower on his whereas mine seems to drop in rpms a little, but I'm running more lift.
Both using a greenhorn wand around the same psi, his carpets are always a little more damp than mine.
Rinse may be a factor, equipment is another, along with method of wanding.
what's IPA?