Everything will be taken from the unofficial Advance Wars Wikia.
CO Powers:
Here is the main page on them. Basically, as units fight, the CO Power meter builds up. The meter is shown, in the original as a curved bar, while in Black Hole Rising and Dual Strike, they are shown in stars. As of Black Hole Rising, there are two levels of CO powers.
The basic CO powers are usable as soon as the small stars fill up, and these will grant small increases. With Grit, his CO Power is Snipe Attack, which increases the range of indirect units by 1 square, and indirect attack is raised to 140% and defense to 110%. Dual Strike increases all other units' power and defense by 10%.
The Super CO Powers are only usable when both the little stars and the big stars are filled up. These are large, nearly game breaking, depending on who is used, power boosts. For Grit, his SCO (Super CO) power is Super Snipe. It increases the range of indirect units by two squares, as well as granting all other powers of the CO Power.
As of Dual Strike, there are Tag Powers. These are added when two Commanding Officers are together in a Tag Battle (That is Two COs on one team). When both CO's power meters are at full capacity, they can unleash a tag barrage which allows them to take two turns in one day. They also unleash their Super CO Powers. In addition, if both COs get along, then they get an additional power boost. If they don't get along, the units can lose power instead.
These are the basics on CO powers, in case Grit gets his chip removed. (I'm actually working on how that would work. If you have suggestions, please AIM me at burnedupthesigns)
Thank you.