Maps rarity/quantity math

Let's say, I have 12 quantity, 15 rarity and 30 effectivity at Atlas. When checking a map, it has 75/33 quantity/rarity, but when I visit it, it says 108/55. Let's dig down these numbers.

I'm not sure about the order of applying bonuses from Atlas Skills, so let's count all options. Let's elaborate on quantity:
(yes, some are pretty retarded, I just wanted to cover all possibilities)

75 + 12 + 30 = 117
75 * 1,12 * 1,30 = 109,2
(75 * 1,12) + 30 = 114
(75 + 30) * 1,12 = 117,6
(75 + 12) * 1,3 = 113,1
(75 * 1,3) + 12 = 109,5
75 + (12 * 1,3) = 90,6
75 * (12 + 30 + 100) / 100 = 106,5

And for rarity:

33 + 15 + 30 = 78
33 * 1,15 * 1,30 = 49,335
(33 * 1,15) + 30 = 67,95
(33 + 30) * 1,15 = 75,45
(33 + 15) * 1,3 = 62,4
(33 * 1,3) + 15 = 57,9
33 + (15 * 1,3) = 52,5
33 * (15 + 30 + 100) / 100 = 47,85

So, there are nowhere numbers close to 108/55. What am I missing?

(Edit: Numbers for quantity are actually incorrect, as there is another quantity modifier coming from the map device itself, but there is nothing for rarity.)

The 30% effectivity is applied to every single modifier one by one and rounded down. At the end the additional flat amount is added on top of that value.

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ParanoikCZE wrote:

(75 * 1,3) + 12 = 109,5

(33 * 1,3) + 15 = 57,9

That's why these two are the closest because only rounding per modifier and the order is missing but you'd have to know the modifiers on the map and you'd have to look up how much quantity and rarity they each give.

Still, another 8% of the quantity (from the map device) is missing in the number. It's weird.

Don't forget that some of that quantity is coming from map quality, and wouldn't be multiplied by modifier effectiveness either.

Judging from the numbers available on maps, I'm going to guess the map was a 20% quality map with one 16/9 mod, and three 13/8 mods.

20 + 16 + 13*3 = 75
9 + 3x8 = 33

Applying the 1.3x effectiveness to each modifier, rounding them down before adding them up, is only slightly off.

16 * 1.3 = 20.8 -> 20
13 * 1.3 = 16.9 -> 16
9 * 1.3 = 11.7 -> 11
8 * 1.3 = 10.4 -> 10

(20 + 16*3) + 20 + 12 + 8 = 108
(11 + 10*3) + 15 = 56

(there are a few other variations on modifier sizes that get just as close, as far as I can tell, but I couldn't hit 55 quantity in-map on the dot; maybe I'm just missing it because I'm tired)