Dear Samantha,
This Level material cost should only be updated by entering the material cost manually.
If the This Level Material Cost is updated from 0 to some other value when you run the Product Structure Cost Roll-up you raise this as a defect with steps to reproduce the behavior.

Best regards
Bengt Johansson

You used the wrong program to remove the THIS LEVEL Material Cost.  1.4.3, 5, 7, and 9 are all related to the master record.  So what you need to do is to use the ITEM SITE  COST MAINTENANCE (1.4.18)  Even if you only have one site as soon as you created a part in 1.4.1 or 1.4.3 the system created a sct_det record which is now site specific so all future changes manually will need to be made through 1.4.18.  By the way as you have now set the default to zero in 1.4.9, it now means that any additional sites you create would have a This level material as zero.

I have to correct a statement made in the last post.

When you use 1.4.1 Item Master Maintenance and 1.4.9 Item Cost Maintenance you modify the item cost at the site the item is linked to in the Item Inventory Data frame.


The site you modify the cost for in 1.4.1 Item Master Maintenance and 1.4.9 Item Cost Maintenance is visible in the Cost frame.


Using 1.4.18 Item-Site Cost Maintenance for this site (site 10-100 in the example above) will give you the same result as you get if you use 1.4.1 Item Master Maintenance and 1.4.9 Item Cost Maintenance.
However, it is necessary to use  1.4.18 Item-Site Cost Maintenance to modify the item cost at any other site than the site in red above. 

But the example you gave was for a different site


So unless you are using linked site costing you have to maintain it through 1.4.18 for Site C1

The screenshot Samantha Cesar provided shows that the cost will be updated for Site C1 when using Item Cost Maintenance (1.4.9). The result would be the same if she used Item-Site Cost Maintenance (1.4.18) for site C1. My point is that the Item cost will be updated for the site you see in the GL Cost Data frame (C1) regardless of which program is used 1.4.1 or 1.4.9. There's not need to use 1.4.18 if there's only one site.