Why is Double Swing better than Frenzy?

I try to understand the difference between the Barbarian skills Double Swing and Frenzy with the Diablo 2 Character Planner.

The items in my example are:

Death Colossus Sword(Equipped)385% ed eth
Fortitude Archon Plate(Equipped)1572 def 1.5 life/lvl 30@
Grief Phase Blade(Equipped)40 ias 400 dmg -25% psn pierce 15 laek
Arreat's Face(Equipped)6 ll 200% def + um
Dracul's Grasp(Equipped)10 ll 120% def 15 str 10 laek
Gore Rider(Equipped)200% def
Highlord's Wrath(Equipped)
Nature's Peace(Equipped)30 pr 11 dr
Raven Frost(Equipped)250 ar 20 dex
Thundergod's Vigor(Equipped)200% def

These are the skills: I maxed out Double Swing and Frenzy with all bonus skills except Berserk.

And these are the calculations:

The calculation says that Double Swing makes 32k damage per second while Frenzy does only 31K damage per second. I think the reason is that Double Swing does 5 hits per second while Frenzy does only 3.5 hits per second. And this is what I do not understand. Although Frenzy adds attack speed and Double Swing does not, the number of hits is lower. Even if I increase the Frenzy stacks to 25 the number of hits is below 4.

The reason may be hidden in the tables, I do not know how to read them.

Can anybody explain how to read the attack rate tables and why Double Swing makes more hits per second than Frenzy?