The hard thing to understand on some of the Configuration settings is that they are session oriented ...

This means that while you may change the sort order to Product Model, 2, that will not be set until a new session is done ...

One way to test this is to use one browser to set it and another to test it ...

Otherwise, in FireFox, for example, you would need to set it and close all FireFox browser windows so that the next time you open it and make a new session then the setting will be reset ...

I tested this using FireFox to set it and IE to check it ... works fine ...

I also tested this using IE to set it and FireFox to check it ... and it works fine ...

There is a Sort Order setting in the Categories/Products to manually set the session sort order by the way ... and once set there, it will hold throughout your current session ...