Hello Faiz

Here is an extract from the "help" option in P6

You are trying to use a fairly sophisticated option here. I hope that by following the step-by-step items below, you will be able to understand and load your requirements

Kind Regards

Stewart

Select calculation options for resource and role assignments

 

1. Choose Edit, User Preferences.

2. Click the Calculations tab.

3. In the Resource Assignments section, specify how to calculate remaining values when new resource assignments are added to or removed from activities.
   
   Choose Preserve the Units, Duration, and Units/Time for existing assignments if you want units, durations, and units/time to remain constant when additional resources are assigned to an activity.
   
   Choose Recalculate the Units, Duration, and Units/Time for existing assignments based on the activity Duration Type if you want to calculate a resource assignment's remaining values based on the activity's duration type specified in the Activity Details General tab.
    

4. In the Assignment Staffing section, specify how you want the module to calculate costs for an assignment when you replace a resource on an existing activity assignment or when you assign both a resource and a role to the same activity assignment.
   
   When replacing a resource on an existing activity assignment, choose to always use the units/time and overtime factor of the current assignment or of the new resource replacing the existing assignment; or, choose to be prompted to select which units/time and overtime factor you want to use each time you replace a resource on an existing activity assignment.
   
   When assigning a resource to an existing role assignment or when assigning a role to an existing resource assignment, choose to always use the price/unit of the resource or role; or, choose to be prompted to select which price/unit you want to use each time you assign a resource and a role to an activity assignment.