Couple BLM questions!

[Shisou]

(snip)Fire (1.5 - I still don't know how I get a short cast fire here... but I don't complain)(snip)

Perchance from the short delay between when Fire III finishes casting and when it applies AF3? It occurs because AF3 gets applied by the damage instead of the cast finishing, which happens at the end of the spell animation. By that point you're already casting Fire, so it still registers as being under UI3.