explain something about fighters and bombers to me

soo i am playing this modded game, one where it will allow two bombers to be launched per cruiser... k... and i click both squadrons into life, take them into battle, and neither of the two carriers ive made so far has produced more than 20% on either of their squadrons? and it wont raise any further?  what gives?  what drives this % and how do i get it to go up past that?  first time ive ran into this.... might be a function of the mod but i doubt that.