Computing Actual cost for activities under progress

Hi all,

I am updating a schedule with some resources assigned. When I update activiites which have started but not completed, I dont get the actual cost after scheduling(F9). I have to go to  Tools --> Recalculate Assignment Cost to see my actual cost update for the activity.

Is there any setting I have to do to calculater this cost automatically after scheduling.

Note: Actual cost is computed for completed activities but not for the ones in progress.

Thanks ,

Sendhil