Reporting Issue for AMount Key Figure

Hi:

We have a report which shows monthly volume by customer with price of a product per 100 lbs. We also have Freight key figure for a 100 lb qty.

I created a calculated key figure using the Freight Key figure from the cube and in the property for calc. key figure I changed aggregation time of calcaulation to Before aggragation. When I run this report for a range of period, The values for this key figure is not showing tha actual value but the some for all periods. How this can be fixed.

Thanks