We now have 4 parts (finished goods and assemblies) that have the wrong standard costs.  When I try to roll the standard costs, DBA gives me a line that says incremental costs for parent.  There is always a large number there and we don't know where it comes from or how to get rid of it. That incremental cost is making the standard cost too high.  Where does that come from?

Trying to work around the system we have also seen this, but it was man made:
We had this problem when we were in a rush - selling an item that had no BOM we changed the part type from A to R and entered standard cost in IN-L-A...just to have a dollar amount for shipping
Then we were suppose to go back in and delete the cost, change the part type back to A and add the BOM when it was established.  Adding a standard cost this way shows up as Incremental Cost and in our example, doubles the cost of the product