I have done it .. I am not sure what it adds to be honest. My process is typically to dry hop in the primary towards the end of fermentation and then crash, move to a brite tank with the next dry hop charge and biofine. Once that is done I move it to a serving keg.
here is an experiment done on the topic https://brulosophy.c...riment-results/
The experiment seems fairly conclusive. Sorry...exBEERiment.
My guess, as these things often tend to be, is that FWs process/equipment led to the double dry hopping procedure, not any flavor benefit. Once the marketing department catches wind of it, though...