This really depends on the version of SQL server you are using.
The resolution of the date time field is to 3 decimal places: For example: 2011-06-06 23:59:59.997 and is only accuracte to within 3.33 ms.
In your case, 09:30:03.0196095 is being rounded up to 09:30:03.020 on storage.
Beginning with SQL 2008, other data types were added to provide more detail, such as datetime2 which has up to 7 decimal places and is accurate to within 100ns.
See the following for more information:
http://karaszi.com/the-ultimate-guide-to-the-datetime-datatypes
I think your best bet is to provide the rounding to the second PRIOR to storing it in SQL server if the milliseconds is unimportant.