About the perks that can do something faster

After the Enduring change, I so confused about how the other perks worked.

Because of Enduring used to "increase the recovery rate" from stun for 75% which means that total stun time while using this perk is

stun time / ( recovery rate + perk buff ) = 2 / ( 1 + 0.75 ) = 1.14 sec

..and after the change that makes Enduring "reducing stun time" for 50% which means that total stun time while using this perk is

2 * 0.5 = 1 sec

So the question is which of these perks are "increase the recovery rate from xxx" or "reducing xxx time"?

- Brutal Strength

- Fire Up

- Bamboozle

- Vigil