Is this logic right? (DRK stance question)

[MerleSirlos]

You do less then base damage with grit + darside
Basedamage - Grit = Gritdamage + Darkside = combined Damage:
100 - 20% = 80 +20% = 96
Basedamage + Darkside = Darksidedamage - Grit = combined Damage:
100 + 20% = 120 - 20% = 96

As you see you do about 4% less damage in grit + darkside as you would do without both.

While the end result is ok (you lose 4% damage), the way you wrote it is horrible. please don't kill math like that D:
the way you put it you just wrote that 100-20% = 96. If you want to do it in multiple step like you intended make it different lines:
* 100-20% = 80
* 80+20% = 96
It might not look like much but it makes things a lot easier to understand.
Other way is to develop it in multiplications. +20% means multiply by 1.2, -20% means multiply by 0.8. so final damage is 100x1.2x0.8=96