Yamaha driver duplicated

I just installed the new Tools download on my CC121 and the update included a new driver. I checked in Devices (Windows 7 64bit) and see that I now have two identical Yamaha USB-MIDI drivers (WDM) listed. I checked the driver details and they are both the same date and rev level ; 01/11/2011 V

However, looking closer at Properties I see that the location for each is different :

Port_#0001.Hub_#0004 and Port_#0002.Hub_#0005

I don’t understand the Hub reference as I do not use a hub.

Has anyone else seen this? What do the port and hub references mean? Should I uninstall them and re-install a new driver?

Have you plugged the CC121 into the same USB port every time?

Yes, I have not changed anything there.