Simming vs Dummy

Whenever I sim my Arcane Mage, Touch of Magi is always the slight winner over my Nether Tempest build. When I do manual tests on practice dummy, Nether Tempest always does about the same damage on multi target and more damage on single target (with 4 charge application kept up). I’ve also noticed my Breath of the Dying minor and Concentrated Flame minor procs 2-3x more often when I use Nether Tempest. Anyone else notice something similar?