It looks like daylight savings aren't being taken into account.  Here's a peek at the AS3 code:
	private function primTimestamp(b:Block):* {
		const millisecondsPerDay:int = 24 * 60 * 60 * 1000;
		const epoch:Date = new Date(2000, 0, 1); // Jan 1, 2000 (Note: Months are zero-based.)
		var now:Date = new Date();
		var dstAdjust:int = now.timezoneOffset - epoch.timezoneOffset;
		var mSecsSinceEpoch:Number = now.time - epoch.time;
		mSecsSinceEpoch += ((now.timezoneOffset - dstAdjust) * 60 * 1000); // adjust to UTC (GMT)
		return mSecsSinceEpoch / millisecondsPerDay;
	}