Polish Book Plugin-How to get Arabic numerals in Book Jacket

[acepenn]

I am using the Polish Books plug-in to add a book jacket to my ebooks. For books in a series, the series number always comes out as a Roman numeral. Unless the series number is a decimal, such as 2.5 which some series have. I want all Series numbers in the book jackets to be Arabic numerals.

So far, I have checked the 'Use Roman numerals for Series' in the Preferences/Look&Feel/Book Details section (I know that really only affects the GUI interface). I have updated the app/resources/jacket/template.xhtml file to use {series} instead of {series.roman}.

But nothing has changed. I have always restarted Calibre after making these changes. The book jacket still generates Roman Numerals for series books.
Is there another setting I am missing? It seems like it should be a simple config change, but I don't know what to change.
BTW, I am on Calibre V9.14

TIA for any helps/ideas!