Business rule setting up Field but does not get saved.

Hi Guys,

I am using CRM Online.

I have setup business rule to set fields "Renewal Reminder", "Final Reminder" and "Termination date" under Opportunity entity based to "Est.Close Date field"

However, the problem I am facing is that the fields are setting correctly but they are not saving until I open the opportunity and click on floppy icon manually to save changes.

How can I make sure that the business rule sets these fields in opportunity and saves the changes?