Your numbers agree with my RAW calculations. I find that tap-Piercing is useful only because you cut down on casting time, i.e. damage is almost directly proportional to charging time, so if you minimise delays and minimise overdamage, and DP would make all the mobs cluster together blah blah.
I save a little MP though. 20-24MP < 30MP for Blizzard.
I want to see what further tweaks they might pull. Getting interesting. I really really hope they do something to Snipe.
Hadriel
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