No, I am using it correctly. The VPN uses a proxy server to get people on the network to the internet. By logging into a VPN you are using a proxy server, it is what will give you what you are calling a "static IP"... (there are many forms of such static IPs, including your own DSL at home)... That you go to the "library" to get the "book" (the proxy's IP address) doesn't change that somebody else can go to the store and buy one or you can just borrow one from a friend...
However, again, most VPNs pass through originating IP information as they are for businesses. When they do, we still catch them as we gather the real IP information on this site.
That you log in through a VPN is no guarantee of anonymity, in fact we almost always will continue to receive the originating IP address.
It is the proxy server that you need, and there are far easier ways to get that proxy IP information, and ways to ensure that the one you are using ensures anonymity. However, their use is questionable at best... You are using somebody's server and they may capture any information that they want while you are using it.