Combo, question

When it says, "Special Attack: Riposte Slash/Pierce dealing 115%/115% damage on each swing, with impact zone: 150%." Does "impact zone:150%" mean that, when riposting, the impact zone mod, which is usually just something like (100% / >100% / >100%) is doing (150%) instead? Assuming Hit Location is also part of the formula and is used like usual? oh and one more thing, does attacking with your main hand in between the first and second Riposte affect either one or does it just split the Riposte combo between the first and last swings but still calculated the same way?