Does fortification buff ammo powers?

Actually, I just recently saw that with James' Incendiary Ammo, for instance, selecting the Fortification "Power Synergy" upgrade increased the damage associated with his incendiary ammo - so long as fortification was active of course.

It does! You can easily verify this by checking your ammo power in the Group Menu with and without fortification activated. E.G. Incendiary ammo Rank 1 is 10% Dmg Activate Fortification Rank 5 Choice 2 Check back to the Group Menu. Incendiary Ammo is 13% DMG

But understand: Buff percentages doesn't sum up. 30% and 40% (eg from Combat Mastery) aren't 70% more damage! You may calculate from the so called increased basic value. In simple terms: Ammo 10% DMG x 40% Buff Combat Mastery = 14% DMG x 30% Buff Fortification = 18% DMG

Nonetheless. If you choose all Ammo Dmg Upgrades and the Ammo Uprgrade in CM, you reach 45% DMG with IA. Activate Fortification and you should have 59%. But alas! There are only 54%. Can't explain this, But 9% more Dmg is better then nomore DMG. ;-)