You're reading the Perk wrong. It doesn't refill ammo after the laser - it refills ammo FOR the laser.
If you have one round left in your magazine and you want to use the laser, the Perk will refill the magazine to let you use it, and the laser fires until your magazine is empty.
English
-
Oh, I see! Thanks for the clarification! I got confused because of the wording in the description. It thought it meant that when you use the laser, it reloads the mag after you shoot it.