This was made mainly for health systems when the projectile needs to subtract an amount of damage from the object it collided with. I didn't want to get/set FSM Float because I thought there could be some loss in there with a busy scene so I put these actions together to simply point at the variable and add or subtract an amount from it.
Every Frame && Per Second is working for continual use and a very basic example scene is included.
Update 15Jul2014: These actions have been cloned in
Ecosystem.