use down circle and then super.
He may be refering to the attack display box that you can activate in the menu during practice. Your concussive wave generates 20 AP then your lvl 1 costs 150 making the box say a 130 net loss of AP occured during the "combo".
It takes 4 + 1/3 of the full blaster combo to make a level 1. That's 130 AP. It takes another 5 + 2/3 of that same combo to make level 2. 300. 14 + 1/3 later and you have a level 3. 730. However, these may have been the original costs.