Why title in wrong a sectional order when using Normal_0 style?

I noticed that the Normal_0 title is far differenet from ms word ,i wondering about that and how to fix it ;

Ms Word

Onlyoffice Word


any advice would be appreciative.
thanks for onlyoffice community.

apperently , in ms word the title 3.1 display normal and in onlyoffice , it turns to 4 , thats makes me confusing .