Splitting rows containing a date interval into as many rows as the nr of weeks of the given interval

You can Add a Custom Column with the formula:

{0..[Number of Weeks]}

Then merely expand that List to new rows, and delete the added column

let

//Change next line to reflect actual data source
    Source = Excel.CurrentWorkbook(){[Name="Table13"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{
        {"Task", type text}, {"Start Date", type date}, {"End Date", type date}, {"Department", type text}, 
        {"Employee", type text}, {"WorkLoad", Int64.Type}, {"Number of Weeks", Int64.Type}, 
        {"Solar Days", Int64.Type}, {"Weekly Mean Workload", Int64.Type}}),

//Add custom column with list of {0..number of weeks}
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each {0..[Number of Weeks]}, type list),

    #"Expanded Custom" = Table.ExpandListColumn(#"Added Custom", "Custom"),
    #"Removed Columns" = Table.RemoveColumns(#"Expanded Custom",{"Custom"})
in
    #"Removed Columns"