I'm so happy to know I haven't gone insane, haha.
Odd thing is that it can't be armor, either, because 777 from a 800 damage spell is less than 3%.
The other day I got hit by a Boulder Roll for 223. So yeah, it's not just from Rain of Ice, I guess I just notice that more cuz I like to play TB more.
Funny thing about creeps is that when I RoI them, they all take different damage. In theory, I should see all 800s above them when RoI hits, right? But on the same cast, they all take 734, 729, 799, 776, etc. On the same cast! Demigods too, so it's not just a creeps/grunts issue.
Maybe there is a random damage generator for AoE spells? I can't think of any single-target spell examples. So 800 damage is actually 750-850 or something like that, for example.
Also, Valor flags only affect grunts, I believe.