If formatting, images, etc. are anchored to the page, rather than to a paragraph or character, there is a lower likelihood of the formatting getting messed up when converting to Word docs. Also, the fonts used should have identical fonts in Word. Keeping the formatting as simple as possible, such as using only one Style for the entire document and keeping word wrap on images inline, will also reduce formatting inconsistencies when converting.
Even Word files being read on an earlier version of Word can have formatting issues. If your files are read only and not going to be edited (other than adding comments) after being converted to Word, I suggest converting the file to PDF (keep the original .odt file for editing and backup). PDFs preserve all formatting and are cross platform (they can be read in pretty much any OS without formatting issues). Most PDF readers can add comments to PDFs if the files are being sent out just for that purpose.