Well I went to Tulum for a short break and was very excited to sync my watch using time and position in cancun.
I exited the airport, held the sync button down until the second hand pointed to t+p and waited.
It synced and pointed to Chicago and set the time back one hour.
However that's not correct... Cancun / Tulum and NYC are the same time.
Kind of disappointed but not sure why the GPS module wouldn't know this.