"Melee" Damage Bonus on Engi Details

In the advanced edition, it makes clear how much benefit your characters gain from levels of skill with hand-to-hand combat. Specifically, green means +10% damage and yellow means +20% damage. However, Engi deal 50% damage to begin with. Does a green level of skill mean they deal 60% damage (additive) or 55% damage (multiplicative).

This question also addresses Mantis who also have their base damage adjusted. I'd imagine they'd work identically but whether the bonus is additive (210% green/220% yellow) or multiplicative (220% green/240% yellow) is not known to me.

This question is agnostic between advanced and standard editions unless they unexpectedly vary.

Edit: This matters more than I thought. Mantis actually deal +50% damage, not +100% damage as listed in the game. I don't know how I missed this for so long. The reason this matters is that a Rock with yellow combat will deal 120% damage with 150 HP (combat rating: 180) while a Mantis with yellow combat will either deal 170% damage with 100 HP (combat rating: 170) or 180% damage with 100 HP (combat rating: 180).

Thus, a rock becomes the ultimate fighter even ignoring the fire immunity in the additive case, whereas they are tied in the multiplicative case. I'm defining combat rating as HP * combat damage%. A higher combat rating means you'll always win in a one on one fight with no other advantages on either side.

Solution 1:

Although there is no specific reference to this from the makers or even online.

I can say based on other stats within the game that this is most likely additive which contradicts most games in how it deals with percentage stats.

I am taking the Engine and Piloting stats as a basis which as the rank goes up it is additive confirmed here Link considering this is also a rank system i can only think that the makers would consistantly use this method.

I hope this helps but there really isn't much about this online and the makers seem content not to make this a complicated numbers game like so many others. Also as mentioned in the comments it is not possible to get the source code for the game and also not possible to mod racial abilities so this is somewhat hard to test.