Duderino,
I am not a lawyer but It is not necessary that EB2 with 0 years experience falls under audit, however, with 0 yrs. experience, there is 50% chances of audit as per the OFLC Audit plan. My PERM was filed under EB2 and 0 years experience and my bad luck , perm turned into Audit, however a lot of my friends got their PERM approved without audit with 0 year experience. To answer your question about the experience before masters, I don't think that counts, neither your experience with current employer counts for the purpose of EB2 unless the future job description is substantially different (50% ) from the one that you are currently employed on.

The information provided is best to my knowledge and you should consult an experienced attorny before making any decisions. I cannot be held liable for any damages whatsoever as a result of your use of information provided by me :)

Good Luck !