I think the difference is due to the leap year bug in Excel:

http://www.ozgrid.com/Excel/ExcelDateandTimes.htm

Select (1/(SUM(Rows)/1846415)) * (CURRENT_TIMESTAMP - '2014-03-04 10:51:00.380')

This won't work as CURRENT_TIMESTAMP is Oracle and SUM(Rows) is not possible without a FROM clause (and possible a GROUP BY).