Combat Style Melee/Dodge Decision Confusion

[unknownhero2827]

I see that by default, Block is 30%, Attack is 40%, and Dodge is 75%. But how does an NPC choose when to make a Melee decision, or a Dodge decision? Is it just 50/50? Or is a dodge decision made if the combined 70% of the other isn't made? Or does the NPC just idle if the 70% isn't chosen?

 

I've looked at the Oblivion wiki. Didn't provide much detail on that.