one with Sazh/Vanille in the woods, everytime you change the weater the enemies respawn and the other was in the Palamecia in chapter 9, there are corridors with lots of PSICOM, if you can get 5 stars in the fights, you'll get A LOT of credit chip/incentive chip.
In one of the corridors, if you explore a little bit, youll find an exit and the game loads the new area where are some PSICOM soldiers and a save point, you cans kill the, save, return to the ship and kill again the soldiers inside, the go out, kill the soldiers again, save, go inside the ship again... and you get the idea..............