ID543 looks at Purchase Orders that have any items on them that are at risk of becoming obsolete (based on decreasing volume trends for the model associated with the item per ID500), where you may already be carrying more inventory than you should be.
When you receive this alert the first thing you should do is check to see if the item can be transferred from another warehouse. If it can, then cancel the item on the P.O. Also research to see if the items being ordered are restock items. If they are then it's possible the items min/max need to be updated. The clicks for this model are decreasing so the inventory stock has to also. Why pay for something that you may have to sell off the remainder of your stock anyway?