If you configure your variable change policy to "on each use" a new value will be used each time. Have you tried this?
You misunderstood, not the variable modifier. If you open the variable manager dialog, select the variable you want, on the right hand side at the bottom of the dialog, you will see the change policy, on each use, on each request, on each page and so on. Select the on each use.
it should, every time you loop around it should be getting the next row (ID)
