FPS Adding VHF?

I have received reports from some areas that Federal Protective Service vehicles are beginning to sprout VHF hi-band antennas in addition to the normal UHF antennas used for the FPS radio system. So what are these antennas for? The FPS car pictured here seems to have a four-antenna array for LoJack tracking or something similar. The reports I've received are usually referring to single VHF quarter-wave or 5/8 wave gain antennas now showing up on vehicles.

Some suggest that they are getting VHF radios for multi-agency interop capability. Others have suggested that the FPS has been and is using the CBP Customs nationwide VHF radio network. I have not personally confirmed this and have not heard any traffic that could be FPS, so I'm not sure about this one.

The FPS, under Immigrations and Customs Enforcement in DHS, currently operates on a national UHF radio system that is dispatched from regional Mega-Centers. Most cities have switched to (or will soon) P-25 digital. Here are the known UHF frequencies utilized by the Federal Protective Service.

406.2000 MHz
406.4125 MHz
406.7000 MHz
407.0000 MHz
407.1750 MHz
407.2125 MHz
407.3625 MHz
408.2000 MHz
408.5375 MHz
410.8000 MHz
411.0375 MHz
413.4750 MHz
413.8750 MHz
413.9500 MHz
414.4750 MHz
415.1750 MHz
415.2000 MHz
416.0250 MHz
417.2000 MHz
417.2500 MHz
417.4250 MHz
417.6500 MHz
419.1500 MHz
419.1750 MHz
419.6500 MHz
419.8750 MHz.