How high can UI numbers get for USB devices

We left the power management on for our USB hub. This has the effect of switching itself off and then switching itself on again when accessed. I don't know when the access happens or when the hub is switched off. One of the devices connected to this hub has the strange behaviour where it updates the UI number whenever it is reconnected. I thought these UI numbers only went as far as 256 but yesterday, the number was up to 932. I've been searching for this on the internet but I can't find the answer. The question is - how high does the UI number go? It is a ULONG so does it go to MAXINT? Edit I

Question by cup on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.