FillDown with a Calculation

This code will handle the task in one query. It shows how you can join from one step into another.

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"MaterialCode", type text}, {"ProdSequence", type text}, {"Operation", type text}, {"Material", type any}, {"Qty", type number}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1),
    #"Added Custom" = Table.AddColumn(#"Added Index", "Header", each if [Qty] = null then null else [Index]),
    #"Filled Down" = Table.FillDown(#"Added Custom",{"Header"}),
    #"Grouped Rows" = Table.Group(#"Filled Down", {"Header"}, {{"Count", each Table.RowCount(_), type number}}),
    #"Merged Queries" = Table.NestedJoin(#"Filled Down",{"Header"},#"Grouped Rows",{"Header"},"Grouped Rows",JoinKind.LeftOuter),
    AddQtyAdjust = Table.AddColumn(#"Merged Queries", "QtyAdjust", each [Qty]/[Grouped Rows][Count]{0}),
    #"Filled Down1" = Table.FillDown(AddQtyAdjust,{"Material", "QtyAdjust"}),
    #"Removed Other Columns" = Table.SelectColumns(#"Filled Down1",{"MaterialCode", "ProdSequence", "Operation", "Material", "QtyAdjust"})
in
    #"Removed Other Columns"