Replacing values in two columns simultaneously under condition

Hey Mic1979 , try and let me know if there is any problem.

let
    RULE_8 = (Input_Table as table, Product_Series_Description as text) =>
    Table.TransformColumns(
        Input_Table,
        {
            {"Body_Material", each if [Product_Series_Description] = "2 way Angle Body Valve" and
                ([Body_Material] = "Bronze" or [Body_Material] = "StSt 316L") and
                ([Stuffing_Box_Material] = "StSt 431" or [Stuffing_Box_Material] = "StSt 316L")
            then "StSt 316L" else _},
            {"Stuffing_Box_Material", each if [Product_Series_Description] = "2 way Angle Body Valve" and
                ([Body_Material] = "Bronze" or [Body_Material] = "StSt 316L") and
                ([Stuffing_Box_Material] = "StSt 431" or [Stuffing_Box_Material] = "StSt 316L")
            then "StSt 431" else _}
        }
    )
in
    RULE_8