I am trying to manipulate an indented bill of material report to identify what the top level assembly is for each component.  I am able to do it in VBA but need it to be done within Power Query... any help would be appreciated. The Macro is really simple and is included.

In the attachment, I start with A, B and C.  Level is the BOM indention level and I am trying to assign the cell (E) "Top Level" with the Component Part Number that is on level 1 above it. I added the output I need in E.  

The real file is about 7000 lines long with indentions up to 10 deep.

Thanks

Tim K