Hi Shakeel,
I would recommend to add one more date type which should store the today's date and time and should have a check box date date only once on.
Use this date type in Date rules for further calculation.This should be easy.
Other option with code is Date rule itself we can include FM which should have logic to check the creation date and time of service request if it exixts else consider the today's date and time for calculation.
Thanks
Ajay
