I am not sure which Version of PHPWord you are using and mine is heavily patched, so line numbers are surely not correct. This is very hardcoded. If you need a patch where you can set the start number from $phpWord->createSection()
you have to wait a little bit. I'm implementing it right now:-)
In Writer/Word2007/Document.php -> private function _writeEndSection
add the following lines:
$objWriter->startElement('w:pgNumType');
$objWriter->writeAttribute('w:start', '0');
$objWriter->endElement();
It should be in the w:sectPr Element.
I added the snippet just before this line:
$objWriter->startElement('w:pgMar');
Change the w:start number to any value.
Hope this helps.