var currentRecord = scriptContext.currentRecord;
var addressObj = {};
var billToId = currentRecord.getValue('parent');
       var recordBillTo = record.load({
          type: record.Type.CUSTOMER,
          id: billToId,
          isDynamic: true,
       });

var addressLine = recordBillTo.findSublistLineWithValue('addressbook', 'defaultbilling', true);
recordBillTo.selectLine('addressbook', addressLine);

addressSubrecord = recordBillTo.getCurrentSublistSubrecord('addressbook','addressbookaddress');
addressObj.addressee = addressSubrecord.getValue('addressee');
addressObj.address1 = addressSubrecord.getValue('addr1');
addressObj.country = addressSubrecord.getValue('country');
addressObj.city = addressSubrecord.getValue('city');
addressObj.dropdownstate = addressSubrecord.getValue('dropdownstate');
addressObj.zip = addressSubrecord.getValue('zip');
addressObj.addrtext = addressSubrecord.getValue('addrtext');

createLine(currentRecord, addressObj);

function createLine(record, addressObj){

	record.selectNewLine('addressbook');
	record.setCurrentSublistValue('addressbook', 'defaultbilling', true);
	record.setCurrentSublistValue('addressbook', 'label', addressObj.address1);
	var addressSubrecord = record.getCurrentSublistSubrecord('addressbook', 'addressbookaddress');

	addressSubrecord.setValue('addressee', addressObj.addressee);
	addressSubrecord.setValue('address1', addressObj.address1);
	addressSubrecord.setValue('country', addressObj.country);
	addressSubrecord.setValue('city', addressObj.city);
	addressSubrecord.setValue('dropdownstate', addressObj.dropdownstate);
	addressSubrecord.setValue('zip', addressObj.zip);
	addressSubrecord.setValue('addrtext', addressObj.addrtext);
	record.commitLine('addressbook');
}