I'm not sure if certain spells are benefiting correctly from certain bonuses:

Focus doesn't affect multi-turn cast spells. If that is by design please update tool tip to say it only lasts one turn. Currently it states that it affects next action.

Certain +% damage to spells aren't stack or stacking only for certain spells?  example:

I have evoker III (+150%), I'm a warlock(+50%), and I have an item that adds +25% damage. That means I should be doing +225% spell damage.  I have 1 Fire shard, 3 death shards and a bunch of others (I'm so dumb - I so should have went death adept for corruption to convert all my shards to death).

Ok cool - so lets take a look:

Flame dart: 8+4 per fire shard.  12 damage base.  39 with bonuses. I've hit for 42.

Soul Burning:  18 + 9 per shard.  18+36 = 54 base.  You'd think that means 185 - although I've hit for 219 before.

Are all spell multipliers additive? or are some multiplied later?