Ah but here's the trick; a rear moveable wing is allowed this year; could that not be used to such an effect at the end of a straight for additional braking assistance?
Only if you start judging whether it makes a difference from a moment where its fully retracted ( open), cause for the most part of the race its in the same place, and if you count from its starting position, or closed, then it makes no difference, cause its in the same place.
When the moveable wing is "in use" it reduces drag; so when released there is more drag which will slow the car in the same way the car will start to slow after pulling out of the slipstream of another car; what I am saying is if a driver is using the wing in closed position to make an overtake; when alongside he could disengage the wing a little earlier to gain a little better braking performance with the additional drag. True I don't what effect this would have on braking but more drag = more slowing down power, like a parachute on a much smaller scale!
I think i got this first time round,im answering your intial question i think....im not sure now....
You asked if it could be used as additional braking assistance so i said it depends on whether you count the wing position from most of the race, or the overtaking oppurtunity. Hope that makes some sense lol.
say if your wings in the predetermined position say at a 45 degree angle, you cant change it unless your overtaking of course. So you could say changing the wing to no drag or fully reflected for speed is giving you negative braking power down a straight, and closing it just puts you right on par ith the car your overtaking, theres no advatange in braking as the car your overtaking has their wing in the downforce position. the advantage is on the straight overtaking. If you close it for braking its just going from negative braking/stopping power, to neurtral, in terms of most of your cars race ( as your wing is in downforce and angled the whole race unless your overtaking), and the car your fighting with.
Alain Prost - Lewis Hamilton - Kamui Kobayashi - Fernando Alonso - Kimi Raikkonnen - Jenson Button