User Event Script Error

Trying to set the line item "Expected Receive by Date" on create, sourced from the "Received By" field on the PO. It keeps pulling today's date in rather than a date in the future. We are using create so that we can edit the PO if certain line items are not forecasted to arrive all on the same date. Can anyone see where we are going wrong?

function userEventBeforeSubmit_SetReceiptDate (type)
{
if (type === 'create')
{
  var count = nlapiGetLineItemCount('item');
  var dueDate = nlapiGetFieldValue('duedate');
  nlapiLogExecution('DEBUG', 'userEventBeforeSubmit_SetReceiptDate', 'duedate: ' + dueDate);
  for (var i =1; i<= count; i++){
    nlapiSelectLineItem('item', i);
    var expectedreceiptdate = nlapiGetCurrentLineItemValue('item', 'expectedreceiptdate');