GMT and UTC are the same. GMT is old reference to the Greenwich Meridian. UTC is the new reference to the Greenwich Meridian. France did not like that all clock were referenced to Greenwich England. So they established UTC as an ISO standard instead. Universal Coordinated Time (order of the initials changed by French language to UTC)
EDT is UTC - 4
EST is UTC - 5
The Q drop graphic in the map and the one you used in >>18395 are in EDT. Date of the drop 10/28. Daylight savings time in effect until 11/5.
However, you are subtracting the EST offset from it. That makes it look like a delta of [0].
The actual delta is [60]