timestamp u/-LuciditySam-

function onEdit(e) {
  var s = e.source.getActiveSheet();
  var row = e.getRow();
  var col = e.getColumn();
  var offsetCol = (col == 2) ? 11 : 12
  var offsetValues = e.source.getActiveSheet().getRange(row, offsetCol, 1, 2).getValues().flat()
  var curDate = Utilities.formatDate(new Date(), "GMT-5", "dd MMM yyyy")
  var curTime = Utilities.formatDate(new Date(), "GMT-5", "HHmm")

  if (s.getName() == "Input" && row >= 2 && col == 2 && e.value == "TRUE" && offsetValues.inculdes('')) {
    s.getRange(row, 13, 1, 2).setValues([curDate, curTime]);
  } else if (s.getName() == "Input" && row >= 2 && col == 3 && e.value == "TRUE" && offsetValues.inculdes('')) {
    s.getRange(row, 15, 1, 2).setValues([curDate, curTime]);
  }
}