When first setting up or reviewing Inventory data it may be discovered that Old Costs, Old Quantities and possibly even Base Costs have not been maintained properly; typically this situation occurs when first setting up Inventory in Vision or if Inventory Management was never done properly and Purchase Orders were not used.

This instruction outlines how to zero old quantities to start fresh with your inventory costing on a FIFO system 
Review 6.4.2 Costing and Pricing Options for more details.

Have users exit the system to allow for exclusive use of the Inventory File.
*Do a full Backup = Utilities, L. Backup System, B. Complete Backup
Select the Utilities menu from the main menu [Shift] & [F9]
Select K. File Utilities
Select K. Data File Utilities
type in the file access code =  PTM-FAC  and press [Enter]
type the File Access Code and press [Enter] twice to confirm
Select T. Inventory Maintenence
Select B. Zero Previous Costs & Quantities
Select A. Zero Previous Quantities  (or)  C. Zero Previous Quantities & Cost

Once the Previous Quantities and costs are zeroed you may also choose to update the Base Cost with Current Cost (this would be highly recommended if your inventory was imported from another system and had badly formatted costs or incorrect costs to begin with.