Do Dual Flurry and Duel Savagery apply to single attacks?
Solution 1:
Josh's answer seems incorrect. I just leveled up, and made a quicksave before putting a point in the 2nd level of the perk (+20% --> +35%). I started a stopwatch and alternated clicking the left+right mouse buttons for 10 seconds. Without the perk, I could pull off 12-13 attacks in 10 seconds, barely. With the perk, I could easily pull off 14-15 attacks. I repeated the experiment twice.