I have tested this in our environment and I've tried both changing the time zone on the EC2 server OS and using your method within the startService script. I changed our time zone from UTC to America/Chicago, which was a change of - 6 hours.
A couple of notes about changing the time zone....
Changing the time zone on the OS caused the time stamps of our loads to be off by 6 hours. All loads were shown as occurring 6 hours before they had actually run. (On AWS EC2 Linux there's a link in /etc called 'localtime' that you have to change)
Changing the time zone in the startService script did not affect the load times on the Schema page.
Both methods affected the 'last modified' date on dashboards and Last Login on the Security page. Any recent modification showed as occurring 'In 6 Hours' - as in - the last login or change was in the future. All times were off by 6 hours.
Just a couple things to be aware of if you change the time zone.
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