Does "Full Salvo" give +25% dmg if you use only one type of ammo?

As the name states
Does "Full Salvo" passive give +25% dmg if you use only one type of ammo?

Yes it does. I'm using Fragmentation rounds mainly, sometimes with Armor piercing rounds and Glacial bolt. For me it works even with weapon swap, although in other thread it was argued against working properly, but I still see dmg increase on my "G" skills screen. The only caveat it is "increased damage" modifier which happens early in dmg calculation, so it increases far less than 25% in skill screen. But increase is there.