Alan,
That is a good option, which I can actually see functionality for on some other things, but I came up with a method that basically calls one Structured BOM format, exports the bom, and then replaces that format I pulled in with the original structure.
this is my code:
'Make sure that the correct structured BOM template is available.
'Import the BOM Tree for exporting too.
Dim oAsmDoc As AssemblyDocument = ThisDoc.Document
Dim oAsmDef As AssemblyComponentDefinition = oAsmDoc.ComponentDefinition
Dim oBOM As BOM = oAsmDef.BOM
Dim filename As String = "K:\Inventor\R2020 Inventor\Customization\BOMTree.xml"
Call oBOM.importBOMCustomization(filename)
'______________________________________________________________________________
'Export the BOM using the BOMTree Structure template
ThisBOM.Export("Structured", "BOM FileTree", kMicrosoftExcelFormat)
'kMicrosoftAccessFormat = Microsoft Access
'_______________________________________________________________________________
'Reset to the orignal Structured BOM format
Dim filename2 As String = "K:\Inventor\R2020 Inventor\Customization\StucturedBOMStructure.xml"
Call oBOM.ImportBOMCustomization(filename2)
So, I have this even to trigger on the close of my top level assembly.
When we design models, A lot of the guys want to "set up" a structure before they start making parts.
My intent was to emulate this spread sheet (minus the formatting niceties). So, every time you close the model you will have an up-to -date look at the status of the model.

It is possible that using the code in Alan's linked post, I could export to a specific template? that's for the future. for now, this gets me around the issue of manual/dual entry of a lot of data. All of the columns in that table are edited either via the BOM now, or using iPropWiz 7.