Yes, it's really opaque right now but more or less it's like: the top behavior fires 40% of the time, the second goes off 24% the third is like 10% and so on. The last few actions barely ever get hit. I'll add a reset button too. Thank you for playing!
And actually, on second thought some of the behaviors are position and angle specific. Melee for instance will be reserved until they are in range, so that they don't waste the cooldown (internal to attacks and shielding, 50 frames shared)