Is Falling Fires bugged?

[Ironhawk]

My experience with falling fires is that it is a bit random tinkthank. Sometimes it will only hit 1-3 guys in the AoE. But then other times it will wipe out whole squads. I use the spell often tho, cause fire magic is so easy to boost in combat via phoenix fire, unlike water and air (which I know can be boosted easily on thier own, but both require eq of some kind.)