Facebook controls the timezone setting on BeLive. Facebook takes time from the timezone setting on your computer, so your broadcast will always be scheduled in the timezone that is set on the device you use. Beware, that "time zone settings" are different from "time settings".
At the same time, each Facebook user will see the time of the post with scheduled broadcast according to their timezone, that's why the time showed can be different, but it is still the same time.
If you are experiencing problems with the timezone on Facebook, the best solution is to go into the "Date and Time" settings on your computer, click "Change Timezone" button, and select the proper timezone for your area.