All date/time values are stored in the database as UTC time. When a user logs into Method, the user's local time zone is determined as well as if Daylight Savings Time is currently in affect from the browser on the computer. The offset amount, in minutes, is used on each screen.
This offset amount adjust the UTC time stored in the database to the local time whenever you show the information in a grid or a field on the screen. So the time changes will be shown properly when DST shifts.
Now I went through some example trying to set values in the past through the API. I was using VB.net. If I set the time to July (7/1/1980 00:00:00) and then convert to UTC, the time showed correctly in Method. If I did the same for January (1/1/1980 00:00:00), the UTC time was off by one hour. I checked the database and the UTC time was off by one hour for January. So it appears .NET is performing a DST offset automatically when calculating the UTC time.
So when creating the time in the past, you may have to make the adjustments before sending the information to the API.
If you need to query the information from the database, use the MethodAPISelect_XML and you'll see the UTC record for date/time fields.
If there is anything else I can help you with/clarify please let me know.