Naxxramas Cultist Kill

Instants are counted from their success event and hard casts from their cast start, because the 3.3.5a client only ever logs one or the other. A hard cast interrupted before it landed still counts — nothing in the log distinguishes it. A few spells, Arcane Missiles among them, this client announces not at all: those are counted from their own ticks instead, one cast per burst of them.

Firecracker Frost 3 casts

Spell	Casts	Per min
Waterbolt	2	17.2
Blizzard	1	8.6