Question about negative MP values

[Memento]

I will soon start working on Goku's Spirit Bomb attack. it will have 3 levels: small, big and huge. Press DvJ to start charging and press A to fire when it's at level 1, 2 or 3.

I got a question about the MP. Is there a way to use negative MP values like MP: -7, that makes the character go to a certain frame (throw the spirit bomb) when MP runs out?

For example:
start (level 1) = MP: 175
Level 2 = MP: -175 (When mana is less than 175, go to frame x)
Level 3 = MP: -175 (When mana is less than 175, frame x)