Black Mage Sanctuary - A Guide to DPS

[Thela]

You need to Tranpose. You'll end up at exactly 2400 mana before the 5th Fire IV.
Transposing has a slew of issues- if you Foul > Thunder 3 > Fire 3, you may get screwed out of the last mana tick which will be a disaster.
If you B4 there, you may still get screwed out of the mana tick (not as disastrous as the previous case)- plus, doing this with a slow F3 is incredibly tight, and any movement will make you force to Tranpose again (and then your AF cycle is thrown into complete disarray) or lose UI and Enochian.
All of these cases are horrid pps losses. At absolute best, it all aligns perfectly and even then you only get like 1 pps for your trouble. Absolutely not worth the risk.

Hm, i could have sworn i was doing 5xF4 several times without transposing (and without umbral heart) but maybe my memory is fuzzy