When you win a combat, the amount of combat rating the enemy has is the amount of gildar you get at the end of the fight.  If you use auto combat, you get what you saw going in to the fight.  If you use the manual combat, the combat rating drops during the fight and your gildar reward drops as well.  I am thinking that the experience your units get is based on the same stat.  This could add up a lot in a multiplayer game and should be addressed relatively soon.  Thanks.