I'm not sure if tabs work, they usually need to be either different browser types or devices, or private browsers (Safari works for this, Chrome does not). Otherwise they essentially generate the same queue ID. So if you have one Chrome window, an incognito Chrome window, they should have separate IDs in the background, but an additional incognito Chrome window will have the same ID as the first incognito Chrome window. Safari will give unique IDs to every private window which is an advantage. Tabs within the same window typically generate the same ID and are basically identical queues if that makes sense. The graphic is pretty accurate, so if the progress bar looks different you should be fine. Keep 'em open til it progresses far enough for you to tell.