Unfortunately to mine, and many other player's disappointment the "carrying an extra fusion grenade" perk doesn't mean you can carry three fusion grenades with the "Gift of the Sun" sunsinger ability. I think this should at least be an option for the armor piece because the way it is now limits your options with the exotic. Having the option to use three grenades or have two and use "Angel of Light" for example would be awesome without being incredibly overpowered. I hope this gets patched if it was intended to work or gets changed so it does allow for three grenades.