[Serusers] What is unique to a call in acc database table??

We are currently working on our Billing system and I was looking over our SER database and noticed sip_callid appeared to be unique to each call but when I looked back in the database I saw a bunch that appeared to be the same??? They were notify messages is this common or do I have to devise a different method? We have the hardest part done that calculates call price by Country Code , City Code, customer assigned rate or default Wholesale/Retail rate. We had it completed when running SanSay Equipment and we were told to make it work with SER. Eric Haskins Lead Software Developer v1010 (954) 272-4961 ext. 206 (727) 239-3823 Cell eric(a)merchant2020.com