I think there is a problem with the different attack types. While defending i use 0 credits thats ok, while attacking i pay my attack thats also ok. But to do a counter attack is a desaster. I pay for an attack and then i am not charging after defeating the enemy. I think the counterattack should work like an attack on an enemy planet without anybody. Means charging will start after defeating the enemy.
For example:
1. Enemy is charging a planet of your faction 48%/30%
2. You are pressing attack in this charging enemy
3. THe winner will go on charging the planet since both paid for attack
At the moment when winning a counter attack you will simply stop the attack for high cost. It is not in the interest of player activity to make people charging planets which cannot be defended anymore by the other faction completely unattractive to attack. Compared to defending there is a difference it costs but at least should start charging then after winnning. THen it is a real counter attack.