Thanks for the replies, confirms my suspicions.
The thinking behind it was, if you can see how long an NPC's ability takes to cast, it's easier to time a cure.
So GroupCure takes 1 second to cast, cast it 1 second before the end of the NPC's casting of 'A spell', cure as soon as the NPC's ability hits. (handy for those stifle/stun aoes).
At the moment I just do it by eye, can nearly see its finished casting, hit cure... etc etc
So was just curious more than anything, a more 'reliable' way than by eye and best guess.
