Attack Speed Spell Multiplier

I have heard in the past that attack speed effects a multiplier on spell damage. (Ex a very slow bows bomb arrow will do less damage then a very fast bows bomb arrow even if both bows have the same damage range) is there any sort of list out there of the exact multipliers for each attack speed rank? If that's confidential I understand. Thank you!

 

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I got you:
Super Slow: 0.51
Very Slow: 0.83
Slow: 1.5
Normal: 2.05
Fast: 2.5
Very Fast: 3.1
Super Fast: 4.3

 

and +tier doesnt affect the spell muliplier

 

Yes, only the base attack speed is taken into account.

 

Thanks!
Strange that there's none that are just a 1.0 multiplier. That would mean that it never does the spell damage listed. I would think the listed spell damage would be based on normal attack speed.