((BWD + Power) x 1.25 (IQ) x 2 (WD%)) x 4 (ED%) x 2 (Skill 20) = A.
A x 3 (Frostbiting) = A3.
((BWD + Power) x 1.25 (IQ) x 3 (WD%)) x 4 (ED%) x 3 (Skill 40) = A.
if your BWD + Power is 1000, then…
20k dmg, 60k dmg when enemy Freezed.
45k dmg.
this is just damage, not DPS. I put in the +300% Ice you had in the original Post.
Power is 75 per Point.
Attack Speed +60% only affects how fast you cast Boomerang, not how fast the Boomerangs fly away and back to you. Boomerangs flight speed is only affected by Boomerang Skill and Celerity.
Damage Per Pierced works better the more enemies there are getting hit by Boomerang.
of course, these are just the numbers you gave me, but not including the per pierced (number of enemies random) and projectile speed (affects DPS, not damage) or any other damage/DPS modifiers.
I hope the links I shared help with future builds.