To change the number of devices displayed in the VoIP/MOS tab, do the following:
Run RegEdit
Navigate to HKEY_LOCAL_MACHINE/Software/Wow6432Node/NetLatency/SwitchMonitor
Create a DWORD entry named DestWebMOSGraphs and set it to the number of devices you want to display.
(Default is 20)
Stop and restart the PathSolutions TotalView service