a job offer is not a source of negotiation
I had an employer I approached for a raise. I showed the value I had brought to the organization, the accomplishments, the leadership, etc. Then proceeded to show the div. manager various (note various) salary surveys that indicated I was severely underpaid. The manager indicated he felt that money was not available in our area. Alas -- I got no raise and began a job search to see if that money was truly available in our market place.
2 weeks later I gave my letter of resignation and suddenly that same manager wanted to talk about meeting the offer. (Which was higher than I had requested 2 weeks earlier).
I decided I did not want to work for a company that forced me to get another job offer before considering to compensate me at market value. So a job offer is not a source of negotiation. Why work for an organization that needs to be coerce into giving fair pay.