Sorry for the math heavy post, I'm trying to understand why people are pouring so many points into precise strikes with math, and it's not adding up for me.

When calculating average damage between non-crit and crit hits, I've been using this formula:

Base damage x (1-crit ratio) + Base damage x crit ratio x (1+ crit damage modifier)

Here's an example:

A stamblade with 80% crit chance, hemorrhage, beast trap and 10% into precise strikes uses a skill that deals 100 base damage:

100 x .2 + 100 x .8 x (1+ .5 + .1 + .1 + .1) = 164 average damage with the skill.

If they were to add 1% more into precise strikes, the damage would look like:

100 x .2 + 100 x .8 x (1 + .5 + .1 + .1 + .11) = 164.8 average damage.

So in this case, adding 1% into precise strikes results in 0.488% damage increase. And interpolating that a bit, if you were to add .2% into precise strikes, it would be like adding .098% overall damage.

Is this math messed up or is it right?