I don't know how did you calculate the 48 damage for the Flames spell. Just to menetion, if you use the aspect of terror damage increas effect, it is recommanded NOT to dual-cast, but only double cast. Dual cast spell is considered one spell, so the Aspect of Terror bonus 15 damage is counted once, while casting the spell separately with 2 hands will count it twice.
Anyway, for the calculation:
base dmg x augmented flames + aspect of terror = 8 x 1.5 +15 = 27 damage / hand so casting it with 2 hands separately: 54 dmg/sec.
Dual cast: 8 x 1.5 x 2.2 + 15 = 41.4. I really can't see how is the 48 dmg/sec calculated :)
I don't know how did you calculate the 48 damage for the Flames spell. Just to menetion, if you use the aspect of terror damage increas effect, it is recommanded NOT to dual-cast, but only double cast. Dual cast spell is considered one spell, so the Aspect of Terror bonus 15 damage is counted once, while casting the spell separately with 2 hands will count it twice.
Anyway, for the calculation:
base dmg x augmented flames + aspect of terror = 8 x 1.5 +15 = 27 damage / hand so casting it with 2 hands separately: 54 dmg/sec.
Dual cast: 8 x 1.5 x 2.2 + 15 = 41.4. I really can't see how is the 48 dmg/sec calculated :)