In cases where a Deal covers territories with multiple time zones , the Deal would become active (start date) or stop (end date) when the easternmost time zone reached the date or the date time. When assessing what “easternmost” means, one should disregard outlying minor possessions of a country. The easternmost time zone for the US would thus be EST or EDT; the time zone applying to Guam, for instance, should not be applied.
 The time zone in Guam is Chamorro Time Zone (ChST), and it is UTC+10 as opposed to the UTC+5 or UTC+4. Note that Guam has it’s own ISO Territory Code (GU).
in one territory it is also possible for sender and recipient to agree a single time zone that is used for all time zones in that territory.
One example where this approach is common is Russia where Deals are often communicated in Moscow time (MSK) for the entire country. A Deal starting, for example, at 09:00 MSK (09:00:00+03:00) would become available for a user in far-Eastern Siberia at 21:00 Kamchatka Time (PETT) and a user in Kaliningrad would see the Deal become available at 08:00 Kaliningrad Time (KALT).