Hi I wanted to know exactly how DOff powers stack. Lets say you have 5 active projectile weapon DOff's who each have a +20% chance to reduce the recharge on torpedoes. Do you then have a +100% chance to reduce the recharge, or do you have 5 separate 20% chances?

What about DOff's that give a flat bonus to a power, such as Warp Theorist DOff's. If I had 5 Warp Theorist DOff's that reduce the turn rate of an enemy ship by 50 for 9 seconds when I use a Tachyon Beam, would their turn rate be reduced by 250 for 45 seconds if I used a Tachyon Beam?

First of all, not all Doff types are stackable. Many of the more 'desirable' ability types you're limited to only having one. (e.g. It would be nice to have more then one Doff that could call down addition Turrets, or addition Mortors, or addition Drones so you could spam the field with your 'toys', but alas, this is not possible...)

The Doffs that do stack do not 'add' their chances, instead, each Doff acts in parallel... So in your example, if you have 5 Doffs, with a 20% chance for an effect, you don't have a single 100% chance. Instead you have 5 chances, each at 20% for an effect. (which also means you have a chance to trigger multiple effects...)

Alright I see the wiki says on some of them whether they are stackable or not. But the wiki page for photonic studies scientist doesn't state a limit. Is this correct? Because I would love to have 5 of them active.

If I understand the math right if I had 5 purples it would work out as:

purple photonic studies officer gives 20% bonus to recharge on photonic abilities
photonic officer cooldown: 5 minutes (300 seconds)

1 photonic studies officer: 300 * .8 = 240 seconds
2 photonic studies officer: 240 * .8 = 192 seconds
3 photonic studies officer: 192 * .8 = 153.6 seconds
4 photonic studies officer: 153.6 * .8 = 122.88 seconds
5 photonic studies officer: 122.88 * .8 = 98.304 seconds

... So actually I could have 4 purples and any quality 5th and be able to chain 2 photonic officer abilities together. Having a permanent cooldown bonus on all BOff skills would be pretty awesome.

Before I start buying up purple photonic studies DOff's I would like to know if there actually isn't a cap on them... Anyone know for sure?

*EDIT: Okay I bought a bunch of common photonic studies DOff's and found out there is a limit of 3. I hope this helps anyone else who was looking at using these.