Edit Chainsaw codes

I'd no idea on how to edit Chainsaw codes that will 100% used instant death kill "only" on enemy that are vulnerable to it, and 100% regular damage if enemy are immune to 
instant death. I do not like when Edgar's Chainsaw use the 25% instant kill effect on boss that are not vulnerable to it. It just a waste of turn.  


C2/2B30: 20 5A 4B     JSR $4B5A      (random #: 0 to 255)
C2/2B33: 29 03        AND #$03
C2/2B35: D0 16        BNE $2B4D      (75% chance branch)
C2/2B37: A9 08        LDA #$08
C2/2B39: 85 B6        STA $B6        (Animation)
C2/2B3B: 9C A6 11     STZ $11A6      (Battle power)
C2/2B3E: A9 80        LDA #$80
C2/2B40: 0C AA 11     TSB $11AA      (Set death/wound status in attack data)
C2/2B43: A9 10        LDA #$10    
C2/2B45: 8D A4 11     STA $11A4      (Set stamina can block)
C2/2B48: A9 02        LDA #$02
C2/2B4A: 0C A2 11     TSB $11A2      (Set miss if instant death protected)
C2/2B4D: A9 20        LDA #$20
C2/2B4F: 0C A2 11     TSB $11A2      (Set ignore defense)
C2/2B52: 60           RTS