Essence Reaver better than I.E??????? (Draven)

I did some testing with draven AA’s and compared the damage from just an essence reaver to just an I.E Axe Damage (both): 168 Essence crit(no axe): 196 I.E crit (no Axe): 245 Essence crit (w axe): 267 I.E crit (w axe): 316 So my theory is with 30% cool down reduction (need one crit attack speed item) you can indefinitely have two axes spinning and you can spam Blood rush. Going essence reaver does not do as much damage but allows consisant damage with always spinning axes and is safer. So tell me why I.E with one crit attack speed item is better than essence reaver with one crit attack speed item on Draven

Test: Standard AD runes Level 18 on practice tool (fully upgraded abilities) Attacked test dummy (100 Armor) Tested with just I.E and Phantom dancer Tested with Essence and Phantom dancer