Our way is always accurate, just make sure all of the users are set up for the correct time zone and time. Or else use the Net Time command accross the network to set everyones time to the Exchange Servers. I do it occationally to sync everyone to the PDC by using a batch file. Do a Search on MS Knowledge Base for the Net Time command.
List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm