[Hairysteed]

I usually disable the weapons I wish not to use upon assigning the attack run.

For example, I am assigning an F-16 loaded with mavericks to attack a T72, so I disable its cannon, since I know it will have no effect on the target and would just be wasting its ammo.

So if you want your A-10 to attack only with CBU's you need to disable all other weapons.