1) It uses the same calculations that the #mystats window does.
2) It does not limit itself by arbitrary caps on haste. The only cap in the equation is the hard 15% cap on the chance for the ability to activate.
3) Currently, there is enough haste capability to stack up to reach the 15% cap.
As for the name, that is all semantics. We can address that as we go, for now lets focus on the actual base of how well it will or will not affect DPS options

And special strike modifiers are buffs or worn focuses that improve these type of abilities (Feral Strike/Death Strike/Flurry Strike)