Quote Originally Posted by RajaVamberaux View Post
Fire II in Astral Fire III does 187.5 potency per enemy;
Thunder does 270 potency if all ticks hit the enemy;
Both have a base cast time of 2.5 seconds.

Using thunder right away as you've described is a definite potency loss:
With 5+ enemies you could do Fire III into Fire II doing 937.5 potency per GCD (versus the 270 potency of thunder - even considering Thunderprocs).

In fact, thunder in aoe situations during Astral Fire is a DPS loss compared to Fire II or Fire I even at 2 enemies.

Fire III -> buffs -> Fire 2 (x2) -> Flare. Period
Base cast time of Fire II is 3.0 seconds.

Your dps is not the dps of one GCD. If you could spam F2 endlessly then your numbers would be more valid, but MP limits that. Also, Thunder is more than just Thunder, it's also Thundercloud procs.

It's around 5 mobs where Thundercloud casting falls behind, but of course getting that many mobs together often involves a long pull, during which time you can get a few Thunders in early thanks to Sprint and Sharpcast.