I haven't tested this extensively...
Run out of Ember Base Camp and go kick a Mahgo in the shin. Let him cast on you. Document what hits and for how much. Re-zone to reset the DP, and do it again, only this time kick off Mantra of Flame first, since all their casts are fire damage. Document.
Now look at your MoF and check it's stats. @ Insp 10 it's 70 seconds with 42% reduction.
My example:
Mahgo Phoenix w/o Mantra: 111
Mahgo Phoenix w/ Mantra: 81
111-(111*0.42) = 64
Huh? Am I missing something?
Me Mantra of Flame and bad math?
GW Monkey