Hi Gryphon
I have no idea why it should be done after the flight control check,
Villas explained it with his OPERATIONAL LIAISON MEETING FBW quote in post #2.
"If the spoilers are left in the extended position after landing..."
It's only a stupid computer. If you don't cancel the signal (i.e. stow the speed brake handle) then the computer is still latched into Ground Spoiler activation.
If you restart the engines in the same condition (handle still armed), then the computer still thinks you want ground spoilers and gives you them. If you Arm Max Auto brakes, the logic will then apply max auto brakes.
There isn't for deployed position but it's not relevant for the case.
It is more obvious in a Boeing because the speed brake handle will be fully deployed. On the Airbus you have to view the flight controls systems page (during the controls check)
that means you have to taxi faster than 72kts
No - that is only to deploy Automatic Ground Spoilers when you select idle power.