setValue function executes, but values not updating

function openCloseCell()  {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var s1 = ss.getSheetByName("Form Responses 1");
  var s2 = ss.getSheetByName("Portal");
  var data = s1.getDataRange().getValues();
  var last =s1.getLastRow();
  var valB= s2.getRange("C4").getValue();
  for (var i = 0; i<data.length; i++) {
    var row = data[i]
    var cell = row[26]
    if (cell == "Closed" && row[0] == valB)
    {s1.getRange(i+1,27).setValue("Open");
    }
    else if (cell == "Open" && row[0] == valB)
    {s1.getRange(i+1,27).setValue("Closed");
    }
    SpreadsheetApp.flush();
  }
}