How exactly damage calculate with gauss weapon bonus?

[m007kuzya]

I try to understand, but my calculations do not match game calculations.

I am attack big robot with my necrowarior.
Big Robot has 8 armor (67% reduction), 20 of 29 HP, 33% damage reduction and 17% ranged damage reduction.
my necrowarior has:
2.1 dmg
1 attacks (x5 members)
1 armor piercing
8 accuracy (67%)
gauss: +5% for each hp? or how it calculate?

so, i try to calculate:
2.1*1*5*0.67=7,04 raw damage
8 armor - 1 Armor Piercing = 7 armor = approx 58,1% reduction
7.04*(1-0.58)*0.5(total damage reduction)=2,04 damage in total.

Bonus from gauss, i guess: 20*0,05%=1dmg
How i must add it to total damage?

In fact, game shows me 2.2 total damage. But i am not understand how game calculate it
I try different method - but not one of then result in 2.2

Anybody know?

[m007kuzya]

p.s.: and also, when i attac robot with other units and drop his HP to 10HP - noting changes in damage shown, necrowarior still make 2.2dmg (4.4 in close range)...
So gauss bonus calculate from MAX HP, not from current?