Skill Growth damage cumulativeness

So I decided to dig into the game files to try and figure out how the damage of skill growth cumulates such as does it:
 

• A: add them together; beginner is damage +16% and intermediate is damage +32% so you get 48%
• B: they are applied separately; skill does 100 damage, beginner adds +16% damage making it 116 then intermediate adds +32% damage making it 153 damage
• C: it does neither of these and damage isn't cumulative only the other effects are.

So in my efforts I figured out that when a skill is growth'd (grown?) it is always "transformed" into essentially another skill (behind the scenes you can't actually see this) with a new ID and is given new effects and parameters and the effects attached to each of these skills has increasing numbers in their parameters to show increases in damage.
But mathematically, they don't add up.

here is the parameter table for wind stalker bow skill "Genoside Rain III"

base skill	damage: +0%
para:	value:
para 1	35
para 2	18
para 3	50
para 4	15
Growth 1 beginner	damage: +26%
para:	value:
para 1	76
para 2	38
para 3	100
para 4	30
Growth 2 intermediate	damage: +52%
para:	value:
para 1	86
para 2	44
para 3	100
para 4	30
Growth 3 expert	damage: +78%
para:	value:
para 1	104
para 2	54
para 3	100
para 4	30
Growth 4 master	damage: +104%
para:	value:
para 1	126
para 2	64
para 3	100
para 4	30

As you can see para 3 and 4 double once and then just stay the same so probably ignore them for now

but if you concentrate on para1 then it goes from 35 to 76 which is plus 41 (117%). after that is 86 which is plus 10 (13%) and plus 51 (145%) from the start. next is 104, plus 18 (17%) and 69 (197%) from the beginning.
I can't make any sense of it.

if anyone who is much better at math than me or latale knowledge can find any way to correlate these numbers please let me know