Delay API call when nested conditions are fulfilled, otherwise continue as normal

Unfortunately, I was not able to make it work. But I eventually found an alternative : 

let
  SecondsWaiting = 65,// 60 seconds wait time between two bunches of 200 queries needed, 65 to be safe
  WaitTime = #duration(0,0,0,SecondsWaiting),
  CallWait = 195, // max 200 API calls per minute, set to 195 to be safe
  // Call GetTL function to generate the list of IDs
  Source = List.Generate(() => 
// Start loop
    [Result = 
      try GetTLInvoices(1) 
      otherwise null, 
      VarPage = 1
    ],
// Call API until no result get turned up
    each [Result]<>null,
    each [Result= 
      try GetTLInvoices([VarPage]+1) 
      otherwise null, 
      VarPage = [VarPage]+1
    ],
    each [Result]),
  // Convert into a table
  ConvertToTable = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
  // Expand data to get my ID list
  ExpandColumns = Table.ExpandTableColumn(ConvertToTable, "Column1", {"id"}, {"id"}),
  DataType = Table.TransformColumnTypes(ExpandColumns, {{"id", type text}}),
  // Count rows to know when the table ends and we'll add a new delay to be safe for future queries in the dataflow
  RowMax = Table.RowCount(DataType),
  // Add an index to be able to keep track of my 'every multiple of 195 wait a minute and 5 seconds'
  AddIndex = Table.AddIndexColumn(DataType, "Index", 1, 1, Int64.Type),
  // Call function GetTLInvoicesDetailsID, queries on each ID
  CallFunction_InvoiceDetails = 
    Table.AddColumn(AddIndex, "CallFunction_InvoiceDetails", 
      each 
        if [Index] = 1 or [Index] = RowMax or Number.Mod([Index], CallWait) = 0
        then Function.InvokeAfter(() => GetTLInvoicesDetailsID([id]), WaitTime)
        else GetTLInvoicesDetailsID([id])
    ),
  DevelopData = Table.ExpandTableColumn(CallFunction_InvoiceDetails, "CallFunction_InvoiceDetails", {"Numéro de Chantier"}, {"Numéro de Chantier"}),
  DataType_Details = Table.TransformColumnTypes(DevelopData, {{"XXX", type text}}),
in
  DataType_Details

Perhaps not the most elegant solution, but it works 🙂

Thank you for your help!