Yes, it is positionally dependent as to when it catches the offending lines. I don't think it's strictly the last one on the list, although its definitely easier for it to catch them at the end. There are times where it can catch things in the middle of a list too, but it would be dependent on the lines around it.
Not sure I understand what you're saying at the end about your confusion. The documentation is available in the admin guides and online help, but its sparse. It does tend to make sense though.
If you posted specific examples, it might be easier to explain them.