Hello Mauricio,

The first question is - who did Dayend, Adagio or ACCPAC? (Also what versions and service packs etc.)

The cost variance account is hit with the difference between the standard cost and average cost for an item when dayend is run. Next is - who touched the average cost? This figure is affected by receipt of goods (Inventory or Purchase Orders) and adjustments (or less likely by a credit note in OrderEntry returning goods to inventory). What is the average cost for this item? When did it change? (Print some of the inventory history reports to see what's been going on with the item.)