Stock Analysis : negative values

Hi,

I have stock analysis report which is getting the data from

1. COPA

2. 2LIS_03_BF

3. 2LIS_03_Bx

4. 2LIS_03_Um

We created the multi provider and calcualted the Value stock value and Value stock Quantity. We are getting the Value stock qualtity perfectly but when come to Value stock Value we are getting diffrent values for couple of material . I went and check we have unassgined storage location for which the BI system is getting the negative values where as in R/3 For MC.9 report for Balck storage location for that material no value exits . Can anyone will tell me why it is their in BW and not in R/3 it is Consignement in R/.3 System

Thanks