Interesting, on my 2014 if I'm close to home and it's in active regen I'll gear down to keep rpms up till I stop in park and then quick rev to 1500rpm again and maintain that till it's done. Doesn't need neutral or park brake on mine.Once Regen is started and Active it can be continue until completed.
YOU must set the Parking Brake, Place vehicle in Neutral , Hold RPMS above a 1000 VIA Go pedal until completed. If it drops out of active Regen because the RPM were dropped below 1000 for more than 30 Seconds it cannot resume until driven again..