They're wrong and mixing it all up.
The button activates the overboost, but just for 5 seconds? So after that you have to deactivate it and activate it again to have 5 secs of overbosst?
I'd say someone over there got to think before writing!
Overboost is for the lower revs, giving you more torque without effecting the maximum bhp-output. It's activating and deactiving itself. There is no "magic" power-button involved like in the M5. Start to believe!
