Gems 21 lvl/ 23 Q

I have a question, maybe I calculing something wrong.
Like Melee pHysical Damage Support:

20lvl - 49% Melee Physical Damage
20q- 0,5% increase melee physical damage per q so- 10% Melee Physical Damage
20/20- 59% Melee Physical Damage

Then:
21/20- 50% + 10%= 60%
20/23- 49% + 11,5%= 60,5%

In my calculate 23q is better, but price is (Harbringer League):
21/20 - 100C+
20/23 - 20C~

Why?!

Gem levels add 1% MORE, while the quality adds INCREASED. You cannot add them up together like you are doing.

In PoE, increased modifiers are all added up together (gems, passive tree, gear). More modifiers are multiplicative. Since you already have a lot of increased modifiers through the passive tree and gear, increased damage isn't as great as it sounds.

Let's say you have 400% increased damage total.

If you add 10% increased, you now have 410%. Your actual gain is 10/410 = 2.4% more damage

If you add 10% more, you now have 440% (400% * 1.1)

But FA 20/23 is better than 21/20?

"

mllody313 wrote:

But FA 20/23 is better than 21/20?

Well I wasn't going to explain every single gem 1 by 1... your post talks about Melee Physical Damage Support which has a More modifier for gem levels, and an increased modifier for quality.

What does faster attack do?
1% increased attack speed per gem level -> going from 20 to 21 gives you 1% increased attack speed
0.5% increased attack speed per quality -> going from 20 to 23 gives you 1.5% increased attack speed

Both are increased modifiers.