Blitzing

I have a questions and an ask about blitzing.
Is this how blitzing works: if during a game a blitz is called the AI selects a play at random from the blitz playbook? if this isnt how it works how does it? because I have noticed teams frequently call plays not in their book?
If this is true could we get an option to set the chance to zero? And could the plays in the blitz playbook be added to the common set of plays available to add to play books? Could we get an option to populate our own blitz set in the future?
Is this how blitzing works: if during a game a blitz is called the AI selects a play at random from the blitz playbook? if this isnt how it works how does it? because I have noticed teams frequently call plays not in their book?
If this is true could we get an option to set the chance to zero? And could the plays in the blitz playbook be added to the common set of plays available to add to play books? Could we get an option to populate our own blitz set in the future?