How do I change RTF Label Format in Librewriter

I have a website that generates address labels in RTF. When opened in MS Word it is pre-formatted to 3x10(3 across, 10 down) labels(Avery 5160). However, when I open the file in librewriter, it formats the file as 3x6.

Please help!

Please generate a sample file, and create a bug report at bug tracker with that sample attached. Also please provide PDFs/screenshots from both MS Word and LibreOffice, and mention your OS and LO version.