Confused about web service Consumer address priority

I’m a bit confused about the priority of the web service Port address between the Binding setting from the WSDL, a Web Service Alias, and the _url parameter.

I’m using IS version 9.7. The 9.7 Web Services Developers Guide has this note on page 227:

I read this as meaning that the _url parameter overrides both the WSDL value and the Web Service Alias setting. However, the table immediately following that note and my experience suggest that while the _url parameter overrides the WSDL URL, any host and port values from the Web Service Alias will override those parts of the _url parameter.

Is there any way to have a Web Service Alias defined, but also have the _url parameter override that when used?