Second add being the one that spawns with the cactus. Sorry for the confusion. It hasn't changed at all. It really depends on your groups DPS. If you do a LOT, you'll only get the initial one that spawns the boss and 1 more. And it's done in 30-40 seconds. If slower, you might have to deal with a couple others. Your choice, depending on healing and tanking ability whether to kill them or just stay on the boss. It's definitely time based for additional mobs to spawn.