Boarding should start from -40 (assembly, PB Q, Hand Luggage check). Preboard into secure area once aircraft is on stand. Board immeadiatly. Gate can shut from -20 if possible (remembering the boarding pass clearly states the gate CLOSING time as -30mins STD) and the minimum any flight deck can push back if passengers missing is -10. This is to ensure aircraft rotation remains punctual throughout the aircraft's 6-10 sector day.
Normal FR turnaround would see doors shut -5 STD for an ontime pushback from the gate.
Its actually all to add to the highly efficient business model of remaining one of the most punctual airlines in Europe rather then someone fancies to clock off early!! Nice idea though.