Hello,
We have tested your HTML using the conversion plugin and the output is the same than the DOCX, it has the correct widths. We have tested it using the conversion plugin based on LibreOffice (version 5.4) that is the recommended one since phpdocx 4.5.
Please check that Tidy for PHP is installed and enabled, and we also recommend you to read the information available on https://www.phpdocx.com/documentation/conversion-plugin/preparing-the-templates-for-its-conversion, that explains how to get the best output when transforming the DOCX; such as fixed widths for tables, rows and cells. A table with a width of 620px is equivalent to a 100% for an A4 page, so you shouldn't exceed that value in an A4 document.
Regards.