so i just did this with just 1 dream and no other gear and this is the damage i get…
Runeword Dream(tiara)
pally 3-2725 damage(Lightning resist 20 240%, salvation 20 80% = 320%syn) 130str 140 dex!
sorc 5-9262 damage(Lightning mastery 20 - 278%) 156 str 136dex!
no other gear, charms or skills, just a fist
why does the sorc do so much more damage?
If I’m not mistaken, it has something to do with how Lightning Mastery is applied; someone can correct me if I’m wrong, but I believe it’s applied twice; once for the damage being added to your attack, and a second time for that damage actually being used. For instance: venom on an assassin gets double boosted by %poison damage for the same reason.
I have no idea if I’m right about this, so if someone else has a better understanding, please let me know!
ok looked up lightning mastery on amazonbasin and yes it says
.applies to holy shock attack damage before it is added, then again using Melee attack.
so if you use a ranged it would only add it once.
interesting
Lightning Mastery scales indefinitely whereas synergies cap out at +320%…
Lightning Mastery starts to scale better than maxxed synergies starting at level 24. Mastery also applies double for melee 
Masteries apply to melee damage, if you have an charm with lightning damage it is also increased by lightning mastery. And it applies to skills ofcourse. So what you got with the aura, is that first the skill is increased and added to your attack, and the result is again increased if you hit an enemy (Like with the charm). And the ranged is actually a bug, it even displays the double increased damage but in reality only deals single increased damage.
And what makes this so crazy high is that it’s calculated after each other, so if LM has x4, it’s not x4 + x4 = x8, it’s x4 x4 = x16.
In addition, the devs were expecting the Paladin Dream users to run conviction aura and already took the double damage in consideration when they punched them numbers on the HolyShock damage.
It used to make for interesting niche builds but it really doesn’t matter anymore, developers killed melee sorcs last patch.