Sheet Metal assemblies indented detailed numbering BOM

Hi,

I have to create an indented BOM for some sheet metal welded assemblies.The issue is that when i crete the BOM with detailed numbering,in the table i have a line for each sheet metal part that has no properties compiled.The blank line refer to same part .I attached a picture with a small assembly.

So i want to know why this line appear and how to remove it.Remove it manually is not an options since i have assemblies with more than 500 comp.

Thank you

SolidworksSheet Metal