Paradox - Kinetic Carbine damage doesn't calculate as expected

[Avalre]

I was messing around in Practice Range, making a build to allow Paradox to deal 100% max health damage in a single combo. For fun, I also was calculating what damage amplification Kinetic Carbine would have with the build. As a way of verifying my math, I was comparing the damage in-game to what numbers I was calculating. I realized they didn't match up, but couldn't figure out why. There's a strong chance I just calculated something incorrectly, but I don't have the time atm to go through and calculate the damage amp per-item. I may get around to it later, and will update/delete this based on my findings if no one else has pointed out where I went wrong.

Items:
Glass Cannon
Pristine Emblem
Sharpshooter
HP Ward
Warp Stone
Combat Barrier
Fortitude
Improved Bullet Armor
Rapid Recharge
Improved Burst
Superior Duration
Escalating Exposure
Soul Shredder Bullets
> Torment Pulse (to proc EscaExpo easily)

Kinetic Carbine Damage Amp with this build (supposedly):
1.1 = Soul Shredder
1.8 = EscaExpo @ 20 stacks
2.35 = Kinetic Carbine dmg amp
1.15 = Kinetic Carbine Headshot Bonus
1.12 = Mystic Vulnerability (-12% Spirit Resist)
4.84 = % Weapon Damage w/ max Glass Cannon stacks (HP Ward, Fortitude, and Combat Barrier bonuses included)
1.95 = Sharpshooter + Pristine Emblem

1.1 * 1.8 * 2.35 * 1.15 * 1.12 * 4.84 * 1.95 = ~56.56x Multiplier
70 = Base Weapon Damage (per burst) at Max Level
56.56 * 70 = ~3959.38 Damage

REALITY:
~2754 w/ Improved Burst proc
~2503 w/o Improved Burst proc