Keep in mind that Cast Time used here means the amount of time for the spell progress bar to reach 75%. Since the calculation is a multiplication, for someone with Fast Cast 1 the spell goes off at 75% * (1 - 0.1) = 67.5%.
Blue Magic Spells that Activate this Trait
Set two of the following Blue Magic spells to get this trait:
Please note that while Blue Mage was originally capable of acquiring the full benefits of Fast Cast, there is presumably a bug currently within the game that causes BLU's Fast Cast to grant only half of the previous and standard Fast Cast I bonus.
Corsair Dice Roll that Activates this Trait
The following Corsair roll to get this trait for party members within area of effect: