@u9023 - You found a little bug. The new style name appears only after clicking one of the other style groups and clicking back to page styles.
May I ask you to please file a bug report and post the bug number here that other can contribute.
https://www.libreoffice.org/get-help/bug/
I used LibO 4.1.5.3 on XP Pro/SP3 for my test. For my test I follow the procedure for which you posted the link in your question.