Lesser Multiple Projectiles and its dmg calculation

Hello, i've noticed something kinda strange with that support gem. It seems that the -30% projectile dmg is kinda more than 30% ?
What i mean is the following. Im having lvl 16 which should give 30%+ projectile dmg, and therefore 30%- projectile dmg.
And it seems that there is some problem in the calculation with those +-30% projectile dmg What i mean is the following :
Without LMP gem i have : 512dps on Lightning arrow.
With LMP lvl 16 i have: 399dps
With LMP lvl 1 i have:357dps


Doing the calc we get the following:
512*0.7 = 358.4 (thats -30%) and then
358.4*1.3 = 465.92! Which is not my case!

Lets try different skill, since some ppl will say its cos of +lightning mod on arrow.
Elemental hit : 646.9 DPS no LMP gem.
512.1 DPS with lvl 16 gem.
453.5 DPS with lvl 1 gem.

First calc:
646.9*0.7 = 452.83(seems they have more numbers after .9)
452.83*1.3 = 588.679!
Once again i cant meet that difference between 512 and 588!
Which is around 518/100=5.88
512/5.88 = 87.07% !
13% difference, please tell me what am i doing wrong in this calculation.

So far i've made a couple of calculations where 0.609 multiplier is the nearest value. Which means that the Projectile DMG reduction is around 40.1%

Looks like it's only showing the damage from the first projectile - so the damage is per-projectile. Multiply it by 3, and that's your DPS.

512 dps without LMP? 357 with an extra 2 projectiles at 30% reduction? So each projectile does 70% damage, and with 3 of them that's 210% damage - so you should be getting 512*2.1 which is 1075.2.

357*3 is 1071, which is sort of roughly 1075.2 because maths rounding addition subtraction matrices I hate maths, anyway you're fine. Just a bug.

'Increased' and 'reduced' modifiers are additive with each other, and 'more' and 'less' modifiers are multiplicative. Meaning that all increased modifiers are added up before multiplying the base value, before being multiplied by each 'more' and 'less' modifier.

Basically, you can say that:

Final_value = base_value * (1 + increased + reduced + increased...) * more * less * more...

This should clarify what you're doing wrong in your calculations. In general, 'less' and 'more' modifiers are much larger differences than an equivalent increased modifier.

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Dreggon написал:

Looks like it's only showing the damage from the first projectile - so the damage is per-projectile. Multiply it by 3, and that's your DPS.

512 dps without LMP? 357 with an extra 2 projectiles at 30% reduction? So each projectile does 70% damage, and with 3 of them that's 210% damage - so you should be getting 512*2.1 which is 1075.2.

357*3 is 1071, which is sort of roughly 1075.2 because maths rounding addition subtraction matrices I hate maths, anyway you're fine. Just a bug.

Its fine showing the damage from the first projectile, but its not true.
As you say 357dps with extra 2 projectiles ,but 357*1.3 = 465.92 should be the answer NOT 399 !
Meaning 465.92 DPS per projectile. Its showing em fine(per projectile), but not the correct value. Now that i've done some calculations more, problem is not in the damage REDUCED but the damage added. Its not 30% at level 16.

@Derelith what you say is:
512*(1+0.3)*0.7 Which means the same what i've been doing ... show the formula please ...

The 512 DPS number already includes some "increased" type damage modifiers so you cannot calculate the 30% increase from LMP as 512 *1.3. You need to start from your base weapon damage and calculate it from there. The 30% increased damage modifier needs to be added to the other similar modifiers. Then finally you multiply the result by 0.7.