About Successful hits..

So hitting say...around 20 monsters with Fireball will reduce it by 40 seconds and hitting thunder about 30 times from multiple strikes ([initial hit+number of charges] x [number of enemies struck]) reduce it faster?

I think it's due to 'spell type' hitting a target.

So Icebolt x 5 hitting a target 5 times is 2 x 5.

But a 5 charge lightning bolt hitting 5 or more target might count as 1 times so 2x1?

Because it's a single cast, rather than multi-cast.

Well I just finally got it after hitting rank 1 Weapon mastery (stupidly easy with a CC+4 Ice Wand btw)...which took about 100000 Icebolts? I'll look into this as I find a large mob.

I am really dissappointed...it goes goes down by hit count. Fireball = 1 hit, regardless of targets hit. I don't have thunder (at least not on my main), but Lightning bolt is the same.