This recovery technique has been proven to be working during official test flights for the Swiss CAA. You can inquire more information from Mr Vuichard directly if you want, his contact data are available in the Swiss CAAs helicopter examiner list:
FOCA - Examiners for pilot examinations
The whole point is: this technique can save lives, e.g. the 4 people which got killed by the CHC crash in 2013. And it is counter-intuitive, because we were all taught pulling collective up during VRS is wrong, as Thomas coupling reiterated. However, it does work because you can get out quickly of the vortex column into undisturbed air left or right of you by applying a 20 degree bank.