Licensing Help

Dear Experts,

I am really confused with Symnatec Licensing for Backup Exec 2012, hence I will give you guys a scenario and you tell

me how many licenses do I need to buy.

Say I have 10 servers that I want to Backup,

I have 1 Exchange + 1 Active Directory + 2 MS-SQL + 1 Oracle Server, and 5 windows servers,

now I want to Backup C drive,System State for all the servers along with the databases and application.

from what I understand I need

10 Agent for windows,

5 Agent for application and databases

1 License for Core product.

but someone is telling me that, if I buy agent for application and database I don't need agent for windows anymore for that server.

please help me.