Below is a sample formula if users are aiming to get the difference of date values in seconds. To add this to a saved search, one has to select 'Formula (Numeric)' for the 'Field' dropdown and add the following formula on the 'Formula' field.
ABS(TO_DATE('12/04/2013 3:56:26','MM/dd/yyyy HH:mi:ss')-TO_DATE('12/04/2013 3:56:15','MM/dd/yyyy HH:mi:ss'))
This can also be used for the fields available for saved searches. For example: