The quantity reported on the Inventory Valuation, Inventory Ledger, and Transaction reports are posted transactions to the All Orders subsidiary ledger where as the quantity on the Inventory Status Details, Inventory Movement, and Items by Location reports shows operational quantities without regard to 'posting status.'
There are essentially 2 major reasons why these 2 reports may be different.
1. Ship Doc that has not be marked as shipped, Returns not marked as "returned", Receivers not marked as "received."
2. A work order allocated but not yet in production.
Ship Docs will show on i.e. Movement report when they are saved, but will not show on the ledger until they are marked as shipped.
Similarly, a work order shows movement when a component is "Allocated" but will not show in the ledger until the status is changed to 'In Production'.