KI

I have a angelo lvl 60 with

Magic shild +4
Thunder +1
Magic attack +1 ( in german bewusstsein)
and super fire bomb +1

allways in a rang tournament he used vs a smiter magic attack but super fire bomb is stronger is very bad

Weather is clear
in 4 fights 3x magic attack and 1x super fire bomb used

[Koenaj]

You answered your own question.
It chooses not to use Super Fire Bomb because the weather is clear.
I suggest getting Fire Bomb instead if you want to kill Plant Monsters.