Date and time range rules

["Kuketayev, Argyn \(Contractor\)" <argyn_kuketayev@fanniemae.com>]

I'm working on time and date based policies, and came across this note:
http://sunxacml.sourceforge.net/guide.html#xacml-time

Is there a problem with time and date functions? If I simply put time
and date values in policies in GMT, would everything work fine?

Thanks,
Argyn