30W
The reason for the issues around the A380 is the distance the ILS is from the Tarmac at KK. At CC and other places it's further away so the aircraft doesn't enter the critical area. The deflection it causes as it turns off is very apparent with one behind, even at 12 miles sometimes. That's why there is such a large buffer spacing wise
I can't speak for arrivals but from a departures perspective the gap is planned once the 380 has pushed and in line with its estimated take off time given by CDM. This then allows radar to arrange as best as possible the sequence / RNAV etc...to coincide with the time coordinated by TWR
It's not a perfect system..