The buttons for Herb Time or Local time only affect how the trips are retrieved from CWA. After you select the time mode you prefer, do a quick sync with CWA to reflect the changes.
After you sync with CWA, that schedule is automatically sent to all your other devices that you're signed into. So if one of your devices is set to sync in herb time and syncs with CWA, then the next time you open a subsequent device (regardless of it's timezone setting) it will show up as herb time.
So, to make sure you get the desired result, just make sure every device that is using your employee number is set to local time.
Also, if you have any one else in your family using CrewBuddy, they don't actually need to sync with CWA. Every time you sync with CWA, their CrewBuddy will automatically be updated.