time not synched between devices

Been noticing lately a big difference between the time my iPhone displays, the time my work mac displays and the time my bosses mac displays. We all have our clocks set automatically (to pacific time), yet there is almost 10 minutes difference between my phone and my power mac, and almost 5 minutes difference between my power mac and my bosses power mac. Any ideas what can be going on here? It's starting to cause problems showing up to meetings on time.