Skeletal arsonists and heavy ammunition question

Skeletal arsonist is a "persistent,fire, detonator" minion
But their bombs are classified as projectiles. Clearly labeled as such, and can be improved with scattershot.
When i expand the arsonist skill, the game calculates the dps around 2700 (per bomb apparently, since it goes up when i remove scattershot)
So i played with instilling emotions into an amulet and added "heavy ammunition" which states "8% reduced attack speed, 40% increased projectile dmg"
But the arsonist bomb dps stays the same 2700

Heavy ammo doesnt specify it has to be fired from a weapon, so i assumed it should apply to my minion bombs. It IS a projectile coming from my skill.

Am i assuming wrong, or is the game just bad at calculating bonuses in the skill info?
Its kind of hard to consistently test the dmg output (not all minions are always alive or in range, not every bomb gets ignited with the firewall etc)

Minions are only effected by things that state minions or allies and debuffs on the enemy. Heavy Ammunition effects your projectiles, not your minions.

Edit:
Some examples to clarify.

Increased fire damage from the tree only effects you, not your minions.
Increased minion damage effects your minions.
Flammability curse on the enemy effects the fire damage of your minions.
Allies in your presence have increased attack speed effects your minions, because minions count as allies.

If you also use the keystone that states that your amulet is applied to your minions and not you. Minions do not have a passive tree. So they cannot anoint a noteable.

Ah.
I assumed and made an ass of me and my minions.

Thank you for the explanation AND the added info about fire dmg.
Very much appreciated.