Google sheets results of Google function query to new range - arrays

Question

I am trying to loop through dates from a selected near date, going a period of four weeks back each time, for 12 periods.
I am doing something wrong in the arrays to push the data to the Results sheet, and it is not working.
Thanks in advance for your help.
function loopDates() {
var sss = SpreadsheetApp.getActiveSpreadsheet();
var ss = sss.getSheetByName('Main');
var results = sss.getSheetByName('Results');
// gets values from Main sheet to calculate new Date
var firstYear = ss.getRange('Main!C3').getValue();
var firstMonth = ss.getRange('Main!E3').getValue();
var firstDay = ss.getRange('Main!G3').getValue();
var target = new Array();// this is a new array to collect data
var headers = [];//inner array
var periods = 13;
var counter = 0;
//loop thru 12 dates and get just the dates for the header
for (var i = 0; i < periods-1; i++) {
counter = counter + 1;
// yearValue,monthValue,day Calculate new Date
var date = [firstYear,firstMonth,firstDay];
var d = new Date(firstYear,firstMonth,firstDay); // must have commas day,
month numbers start at 0
var numberDays = 28;
var countBack = 2*numberDays * 24 * 60 * 60 * 1000 + 3* 24 * 60 * 60 *
1000;
//sign must be '+' since 'offset' is subtracted
var NewDate = new Date(d.getTime() - countBack);
ss.getRange('C5').setValue(new Date(NewDate)).setNumberFormat('mm dd
yyyy');
headers.push([NewDate[i]]); // inner array
}
target.push(headers); // outer array
//Write to Results sheet
var ss = sss.getSheetByName('Main').getRange('A1').setValue(counter);
results.getRange("A1").offset(0, 1, target.length).setValue(target);
return target;
}