About fire 2?

[StouterTaru]

Wow, well done for reverse engineering my ballpark calculations.

And yes, I incorrectly plugged in x1.5 instead of x1.8 for AF3.
It doesn't change the overall effect though, there's still a similar gap between the rotations with and without Fire II. In fact the gap is bigger, as the difference is amplified by the AF3 increase.

I plugged in an insta-casted spell as 0.5s to account for general delay and rounded the overall rotation up to the whole second.

You're still on 3 mobs, and swiftcast Flare still has a GCD recast (during which you can Transpose if you use it for the 2nd Flare, and cancel out the time used for Swiftcast) so the time cut off would be 0.6 GCD; less than 3 seconds.