Proportion mod: combat defence plus

[jowe01]

In proportions, engines give cdp-bonuses. Especially for fighters, these are considerable. My question is, are they also cumulative? If not, are cdp-bonuses from different components/hulls/etc. cumulative or multiplicative? I did a quick search here but did not find anything (though I sure there must be something but maybe I just did not use the right keyords).

Also, are the "to hit" chances which SE4 gives in tactical combat before or after deducting cdp-bonuses of the target. I would guess before because in my Last fight, my fighters always had a 70% chance to hit, while in reality, they only hit in about 25% of all cases.

One more question: Is the "to hit" chance calculated separately for every fighter in a stack or is it one chance for all.