How Time Values are presented in eLynx Application

API calls report tag value timestamps in UTC.  You will see all the timestamps in the JSON file have a "+00:00" indicating UTC time.
 
As far as the CST Offset setting in Tag Details, that value is solely used to calculate the Contract Day rollover time.  No timestamps are changed based on the CST Offset.  For example, if the Contract Hour on the tag is set to 8am, and the CST Offset is +60, then the eLynx system will know that the first reading after 9am Central is the new previous contract day value.
 
This contract day value (both first known for the day and last known for the day) is then used in reports if a user wants to view data as Production Day instead of Calendar Day.  The built in Marketing Report in the eLynx app is a good example of this.
 
The Contract Hour and Offset are set at a Tag level as opposed to a Device level.  This allows operators flexibility.  For example, some operators use a Contract Day of midnight to midnight for tank levels but keep their oil/gas/water measurement at 7am to 7am.

Timestamps viewable in the eLynx app are adjusted based on your browser timezone.  So a user with a browser in the Eastern timezone will see timestamps adjusted for their timezone.  If they were to take a screenshot and compare it with a user's browser in the Mountain time zone, the timestamps would look different but the values would match for each timestamp in their respective timezone.