Disclaimer: I've read the destruction guide, and I know it's mastery>crit as destro gosac. That is not what I'm asking for.
This is not a post where I ask about information I could've found in the sticky destruction guide, this is a request for the mathemathics and exact reasoning behind why mastery becomes so good with GoSac. Is it because of the 15% increase that mastery becomes 15% better, is it just so simple as that? Or is there a more complicated reason?