From Dark and Darker Wiki
"Cooldown Reduction reduces the cooldowns of skills/perks. Reduced cooldown length = Base Cooldown * (1 - Cooldown Reduction)
Note that perk cooldowns are in the form of a buff/debuff and are additionally affected by Buff/Debuff Duration. Reduced cooldown length = Post buff/debuff duration cooldown * (1 - Cooldown Reduction)"
Since some skills/perk also is affected by Buff/Debuff, how do you implement that to the total skill's cooldown time?