2 CPU license means that you can install your IS/Broker on any hardware supporting upto 2 CPU’s. That does not mean 2 different physical servers.
When you say you want to install the IS on 2 servers with quad core processors you will need 2 separate liscences for each of your servers for a quad core processor type. Its 4 times the cost.
#webMethods#Integration-Server-and-ESB