That does make sense. She'd said you hit it once for heating and twice for cooling.
No, it's just the exact same as preheat, It'll heat OR cool based on the climate settings and the cabin temp.
There is also a "summer-opening" mode, press and hold the unlock button, and the windows will open. This is useful when sunny to just let the hot air out as you approach across the car park!
(you can release the button when they are partially open to stop opening fully - though you cannot remotely shut the windows as you can on a merc)