He took the patk and multiplied by the base speed of the weapon to get a normalized "weapon power" the extra factor is to account for hte haste on the sword.
SA on duals -> health... not going take that into account
Calculations are basic (p.atck)*(attack speed)
= (patck)*(bonus to attack speed due to SA)*(base attack speed for type of weapon)
This is a good way to compare weapons, since the number you get fomr the multiplication really means nothing.
I took into account the initial p.atck of both weapons as given by you.
Talum is a fast attack speed weapon. Fast attack speed = 379 multiplier
Duals are normal attack speed = 325 multiplier
Talum haste = 1.06 multiplier.
Again these calculations are only good for comparison purposes.
The result of the calculation means nothing except to see what one is higher than the other.