Timestamps/Queries mismatch

I have a system with 10+ OPC servers in multiple time zones, the Ignition gateway in the EST timezone, and databases in the EST timezone. In the project general properties, the timezone behavior is set to Gateway Timezone.

There is a transaction group setup on a hourly schedule to write tag values to a database table.

There is a window in the project with a table that queries the database using two dropdown calendars for the start and end dates (inclusive).

The dropdown calendars are set for 12:00am January 6 as the start date, and 12:00am January 7 as the end date.

The query results show that the t_stamp values begin at 23:00 1/5/15 and end at 22:00 on 1/6/15.

Any ideas what can be causing this disparity? The ignition system and the database are in the same timezone, so I am not sure why the query is returning with different t_stamps than were selected on the dropdown calendar.