1. In Store Operations select Reports > Items > Value List
2. Run this report -- this will run as of today
3. Go to Reports > Items > Item Movement Report 
4. Highlight Date and set the Range to Custom
5. Set the filters from [specific date] to today
6. Subtract the total inventory cost per Department or Category from the Inventory cost on the Value List Report
Note: for additional fields right click on the report and select 'Hide/Unhind Columns' then select the appropriate fields to hide/show