FF6: Casting from HP - Bloodmage?

I think this would be a good point for interception:

Code:

C2/4EF2: 20 08 4F     JSR $4F08    (Determine MP cost of a spell/attack)
C2/4EF5: 99 20 36     STA $3620,Y  (save MP cost)

Intercept JSR $4F08 with a new routine.