TCPDF无法正确识别格式

I am trying to do a page group, Although it is not working. Right now it is doing page 1 of 4. I need it to number the pages by group. So there will be a total of 4 pages and I need page 1 of 2 then to start over page 1 of 2. class ManafestPrint extends TCPDF {

  //Page header
    public function Header()
    {
        global $pickUpDate;

        // Set font
        $this->SetFont('helvetica', 'B', 20);
        // Title
        $titleHTML = '
                <table width="100%" border="0" style="font-weight: bold; font-size: 9pt;">
                    <tr>
                        <td width="25%" align="left">PICK UP DATE: '.$pickUpDate.'</td>
                        <td width="50%" align="center" style="font-size: 16pt;">SHIPPING MANIFEST</td>
                        <td width="25%" align="right">Page '.$this->getAliasNumPage().' of '.$this->getAliasNbPages().'</td>
                    </tr>
                </table>
            ';
        $this->writeHTMLCell(280, 25, 7, 5, $titleHTML);
    }
}

This is my page layout

        $pdf = new ManifestPrint('L', PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);
        $pdf->SetMargins(0, 12, 0);
        $pdf->SetAutoPageBreak(true, 10);
        $pdf->startPageGroup();
        $pdf->AddPage();
        $pdf->writeHTMLCell(280, 0, 5, 15, $shipperCarierData, 0, 0, false, true, 'C', true);
        $pdf->writeHTMLCell(280, 0, 3, 35, $tableData, 0, 0, false, true, 'C', true);

        $pdf->AddPage();
        $pdf->lastPage();
        $pdf->writeHTMLCell(280, 0, 5, 160, $disclaimerHTML, 0, 0, false, true, 'C', true);
        $pdf->startPageGroup();
        $pdf->AddPage();

        $pdf->writeHTMLCell(280, 0, 5, 15, $shipperCarierData1, 0, 0, false, true, 'C', true);

        $pdf->writeHTMLCell(280, 0, 3, 35, $tableData1, 0, 0, false, true, 'C', true);



       $pdf->AddPage();
       $pdf->lastPage();
       $pdf->writeHTMLCell(280, 0, 5, 160, $disclaimerHTML, 0, 0, false, true, 'C', true);
       $pdf->Output('print_manifest.pdf', 'I');

Turns out my page numbering was set up incorrectly. In my header I needed to change this:

public function Header()
    {
        global $pickUpDate;

    // Set font
    $this->SetFont('helvetica', 'B', 20);
    // Title
    $titleHTML = '
            <table width="100%" border="0" style="font-weight: bold; font-size: 9pt;">
                <tr>
                    <td width="25%" align="left">PICK UP DATE: '.$pickUpDate.'</td>
                    <td width="50%" align="center" style="font-size: 16pt;">SHIPPING MANIFEST</td>
                    <td width="25%" align="right">Page '.$this->getAliasNumPage().' of '.$this->getAliasNbPages().'</td>
                </tr>
            </table>
        ';
    $this->writeHTMLCell(280, 25, 7, 5, $titleHTML);
}

}

to this:

 public function Header()
    {
        global $pickUpDate;

        // Set font
        $this->SetFont('helvetica', 'B', 20);
        // Title
        $titleHTML = '
                <table width="100%" border="0" style="font-weight: bold; font-size: 9pt;">
                    <tr>
                        <td width="25%" align="left">PICK UP DATE: '.$pickUpDate.'</td>
                        <td width="50%" align="center" style="font-size: 16pt;">SHIPPING MANIFEST</td>
                        <td width="25%" align="right">Page '.$this->getPageNumGroupAlias().' of '.$this->getPageGroupAlias().'</td>
                    </tr>
                </table>
            ';
        $this->writeHTMLCell(280, 25, 7, 5, $titleHTML);
    }