Shield Skill

Hey devs, got a question for you.

I was curious about how the mechanics of this work and would like a bit of an explanation.

You see, I have a character that has maxed out shield skill and happens to be a Spear Master first and foremost.

How exactly does the shield skill tie into the block bonus?

For example, my character wields a large shield which is a +10 block base teched with block V which is +16 block chance. Now, with the passive ability of Block Bonus from Spear Master, that's +20, further to tie into that is Employ Shield, an ability that increases the chance to block chance an additional +20.

Now, all together, (and while Employ Shield is active), that calculates to +66 block chance. Where does the shield skill come into to play here or does it even have an effect? Would it increase that block chance further? At what rate would it increase the block chance?