it´s not an early applying of DRS.They run the flap open though those parts of the track where you need good downforce!
If the Wing sheds 10 or more % of vertical force at that sort of speed with the open slot it´s more than obvious that they still have more downforce than the rest of the field in this area.BUT with that approach you will also have ALOT more downforce at slower speeds ,as you close the DRS and find downforce ...the real benefit is therefore in those areas where they don´t use the DRS.As they can carry massive low speed downforce.
They just strike a different compromise compared to the opposition and opt for a higher total drag and a high speed balance shift towards more rear end downforce.
Considering they cannot use as much exhaust blowing as in Qualy ,this added downforcee will help their race balance maybe at the cost of top speed.
the KERS is just there to avoid losing out at the start as this concept is not designed to enhance overtaking .