How to prevent chapter numbering from increasing when converting .doc/.docx files to .odt and .mtm formats?

Question

opendocument

Hello.

I am working with .doc and .docx files that need to be converted to .odt formats and then from .odt to .mtm text format.
Source .doc(x) documents have automatic chapter numbering. The main headings have numbering in the Heading1 style (1. Chapter 1). Subheadings related to the main headings are numbered in the Heading2 style (1.1, 1.2, 1.3), subheadings related to the first subheadings are numbered in the Heading3 style (1.1.1, 1.1.2) and so on.

The problem is that during the format change (in odt and mtm) all numberings increase by 5. The first chapter (1) becomes the 6th chapter, the heading 6.5 becomes 11.5, and so on.

How to prevent it? Where does the crash occur?

P.S, I tried the conversion using the usual save-as command, and using convertapi in Python, and even using free online converters like Zamzar, Convertio, and CloudConvert. The problem remains the same.

P.P.S here is a copy of the original numbering.


Thanks for your help and attention.