Mass-effect – Why do some celestial objects “pulse” on the Galaxy Map

Based on my own testing, it looks like you get 1% for each 6 points invested in the tree. As Mad Scientist pointed out, the value displayed is the total.

Since it's also additive with other boosters, you won't generally get 5% more than your current value. For example, if you have +20% already from other sources, and then get a +5% from this, your original value of 300 is displayed as 360 from the other bonus. When you add this skill, it will go to 375. Since 5% of 300 is 15, you get that, rather than 5% of 360.

To specifically answer your question, I do not think they deliberately made it confusing.

Health Regeneration and Shield Regeneration are not affected by Power Restoration and Defense.

It's reasonable to assume that other stats that affect health or shields but lack the Restoration keyword are unaffected as well.

I tested whether or not Regeneration was affected via the [Team Support] power with [Rank 6 - Life Support] by monitoring my health changes directly through Cheat Engine.

Swapping from [Rank 4 - Squad Offense] to [Rank 4 - Support] did not change the amount of health I regenerated at all; deploying my [Assault Turret] took me from 200 HP to 290 HP every time.

The Defense keyword is probably intended to cover both Damage Resistance and Damage Reduction, as it doesn't seem to actually match any other existing stats. Unfortunately this is very difficult to test as the game simply does not provide enough information.

I'm not convinced a skill like [Backlash] is covered by the Defense keyword despite what the gosunoob article claims, though the [Rank 6 - Shield Resurgence] upgrade is covered by the Restoration keyword.

Unless you're constantly using powers like [Charge] or [Energy Drain] that explicitly grant some form of Restoration, the Power Restoration and Defense stat seems useless. I suggest avoiding it unless your build revolves around powers like these.