Negative Costs???

[giusba71]

Help! I've found a negative cost!

   

Note that in system parameters the Waighted Average Costing is selected.

Looking at the movements I can't understand how this is possible.

   

There are only two deliveries from suppliers at 2.57 and 2.755.
Sometimes I've used the funcion of "cost update for BOM items" in utilities, could is this the reason? This funcion could affect the BOM components costs?

Now I'm scared that all the items costs are wrong so the inventory valuation report.
What can I do?
Exist a cost update pocedure that can check/rectify all the item costs or a funcion that mass set up the standard costs looking at the suppliers deliveries?

Help please.
Giusba