"Search Threads a Week Ago and Newer" is this a 168 hour search?

Just out of curiosity, it’s not terribly important in the grand scheme of things, when I do a search for threads and set the time frame as a week ago and newer, does that show results from:

The beginning of the day, seven days prior to the search?
Beginning of the day when? Chicago Reader Inc Time?
Seven days prior based on the Time Zone for which I am logged in?

or is it results from

168 hours prior to the search?

And “Last Month and Newer Searches”?

Beginning of the day on the same numbered day one month before?
What would happen for a search done on March 29th? Default to Feb 28th?

or would it be

744 hours (24 x 31) regardless of the month (search done on March 29th goes back to Feb 26th)?
Or maybe a standard 720 hours (24 x30)?

Uh, not sure. I don’t know what it uses as a reference point when calculating these values. I would think it would tend to use a fixed point, wouldn’t you? Like midnight or 6:00 a.m. or whatever, that would be the most logical.