Heading numbering in nested DITA files

The default PDF output for nested DITA <title> elements in a ditamap is to number the top two titles in the hierarchy 1, and 1.1. The numbering is assigned via the title.0 and title.1 FrameMaker paragraph tags (which I assume are applied from the files in C:\Program Files\Adobe\Adobe FrameMaker 2020\Structure\xml\DITA\outputTemplates). 

I would like to have 4 levels of section numbering, i.e.,

1.

1.1

1.1.1

1.1.1.1

I added numbering to the title.2 and title.3 paragraph formats in the ditabase1.3.template.fm file and imported the file here:

However, the numbering didn't show up in the PDF. What am I doing wrong?