Importing Files from Folder with same filename

I'm using Query Editor to load multiple CSV file from a folder tree with the same filename. I want to change to source name of each file with a new name I can extract from the file path.  

If I combine the files with out any column changes, I will get a Source field with the same filename.

let
    Source = Folder.Files("C:\Users\ttt\Desktop\BITest3"),
    #"Invoke Custom Function1" = Table.AddColumn(Source, "Transform File from BITest3 (8)", each #"Transform File from BITest3 (8)"([Content])),
    #"Renamed Columns1" = Table.RenameColumns(#"Invoke Custom Function1", {"Name", "Source.Name"}),
    #"Removed Other Columns1" = Table.SelectColumns(#"Renamed Columns1", {"Source.Name", "Transform File from BITest3 (8)"}),
    #"Expanded Table Column1" = Table.ExpandTableColumn(#"Removed Other Columns1", "Transform File from BITest3 (8)", Table.ColumnNames(#"Transform File from BITest3 (8)"(#"Sample File (8)"))),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded Table Column1",{{"Source.Name", type text}, {"X", Int64.Type}, {"Y", Int64.Type}, {"Z", type number}})
in
    #"Changed Type"

If I make any changes to these columns, the "Source" Column is removed when I do the combine.  I was trying to do several column changes and end up with "Content" and "TestName" folders:

let
    Source = Folder.Files("C:\Users\ttt\Desktop\BITest3"),
    #"Invoke Custom Function1" = Table.AddColumn(Source, "Transform File from BITest3 (8)", each #"Transform File from BITest3 (8)"([Content])),
    #"Renamed Columns1" = Table.RenameColumns(#"Invoke Custom Function1", {"Name", "Source.Name"}),
    #"Removed Columns" = Table.RemoveColumns(#"Renamed Columns1",{"Source.Name", "Extension", "Date accessed", "Date modified", "Date created", "Attributes", "Transform File from BITest3 (8)"}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Removed Columns", "Folder Path", Splitter.SplitTextByDelimiter("\", QuoteStyle.Csv), {"Folder Path.1", "Folder Path.2", "Folder Path.3", "Folder Path.4", "Folder Path.5", "Folder Path.6", "Folder Path.7"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Folder Path.1", type text}, {"Folder Path.2", type text}, {"Folder Path.3", type text}, {"Folder Path.4", type text}, {"Folder Path.5", type text}, {"Folder Path.6", type text}, {"Folder Path.7", type text}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Changed Type",{"Folder Path.1", "Folder Path.2", "Folder Path.3", "Folder Path.4", "Folder Path.5", "Folder Path.7"}),
    #"Renamed Columns" = Table.RenameColumns(#"Removed Columns1",{{"Folder Path.6", "TestName"}})
in
    #"Renamed Columns"

But once I try and Combine the files, I do not konw how to include this newly created Column "TestName" as part of my data set.

let
    Source = Folder.Files("C:\Users\tchiles\Desktop\BITest3"),
    #"Invoke Custom Function1" = Table.AddColumn(Source, "Transform File from BITest3 (8)", each #"Transform File from BITest3 (8)"([Content])),
    #"Renamed Columns1" = Table.RenameColumns(#"Invoke Custom Function1", {"Name", "Source.Name"}),
    #"Removed Columns" = Table.RemoveColumns(#"Renamed Columns1",{"Source.Name", "Extension", "Date accessed", "Date modified", "Date created", "Attributes", "Transform File from BITest3 (8)"}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Removed Columns", "Folder Path", Splitter.SplitTextByDelimiter("\", QuoteStyle.Csv), {"Folder Path.1", "Folder Path.2", "Folder Path.3", "Folder Path.4", "Folder Path.5", "Folder Path.6", "Folder Path.7"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Folder Path.1", type text}, {"Folder Path.2", type text}, {"Folder Path.3", type text}, {"Folder Path.4", type text}, {"Folder Path.5", type text}, {"Folder Path.6", type text}, {"Folder Path.7", type text}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Changed Type",{"Folder Path.1", "Folder Path.2", "Folder Path.3", "Folder Path.4", "Folder Path.5", "Folder Path.7"}),
    #"Renamed Columns" = Table.RenameColumns(#"Removed Columns1",{{"Folder Path.6", "TestName"}}),
    #"Invoke Custom Function2" = Table.AddColumn(#"Renamed Columns", "Transform File from BITest3 (9)", each #"Transform File from BITest3 (9)"([Content])),
    #"Removed Other Columns1" = Table.SelectColumns(#"Invoke Custom Function2", {"Transform File from BITest3 (9)"}),
    #"Expanded Table Column1" = Table.ExpandTableColumn(#"Removed Other Columns1", "Transform File from BITest3 (9)", Table.ColumnNames(#"Transform File from BITest3 (9)"(#"Sample File (9)"))),
    #"Changed Type1" = Table.TransformColumnTypes(#"Expanded Table Column1",{{"X", Int64.Type}, {"Y", Int64.Type}, {"Z", type number}})
in
    #"Changed Type1"

Any help would be greatly appreciated. 

Thanks,

Todd