Twin Terror and calculating crit chance

I have taken all passives running to and including Twin Terror, effectively giving me 125% increased Weapon Critical Strike Chance while Dual Wielding.

From my understanding this increases the base weapons crit chance. For example, a 6% crit chance weapon will thus become 13.5% [6% * (1.25 + 1)]. This is the local crit chance.

I have other passives that increases the Global Crit Chance, say I have 200%. This would bring my crit chance to 40.5% [13.5% * (2.00 + 1)].

Is this correct? Because I've always used the [local crit chance] * [global crit chance] formula, and never had issues with calculation. Now that I've started dual wielding daggers and taken twin terror, the character panel indicates a different crit chance.

Twin Terrors does not increase base weapon crit chance. Nothing does, besides local crit chance on the weapon itself. It stacks additively with all other sources of increased crit chance.

I'm confused. Isn't the base weapon crit chance the same as local crit chance? How do I calculate twin terrors into the equation?

Base crit chance is the actual crit number displayed in the weapon stats. So for example on this weapon:

The base crit chance is 10.72%. That cannot change unless you change the local crit chance mod.

Local crit chance is the usual term for the crit chance mod that appears on weapons and increases the weapon's base crit chance. For the above wand the local crit chance is 34%.

Everything else (from gear or the tree) is just increased crit chance, and all stacks additively. This includes global crit, spell crit, weapon-specific crit, twin terrors, all that stuff. When you're calculating your crit chance in this case, you literally just add the 125% from the twin terrors cluster to your 200% (or whatever) global to get 325% increased crit chance, and multiply your weapon crit by that (+ 100%).

Oh that's such as shame :( And here I though twin terrors was an OP node. haha

Thanks for the clarification!