On a Windows platform I use &CHAR(13)&CHAR(10) [CR+LF] instead of just &CHAR(10) [LF] which I use on a Linux platform or just &CHAR(13) [CR] which I would expect to use on a MAC platform
Those are the conventions for plain text files on those systems. Although I believe Mac OSX uses LF, same as Unix, while Mac OS up to version 9 used CR.
Even in the case of plain text, now that files are so readily transferred between systems, most decent text editors cope fine with all 3 formats regardless of which system they're running on.
Do I over complicate the process?
For LibreOffice documents, I think you do. What do you do in a document which might be transferred between different systems?
Does CHAR(13) in a LibreOffice formula on Mac even have the intended effect of splitting lines? Come to that, does LibreOffice even run on Mac OS 9 or before? I suspect LibreOffice only uses CHAR(10) regardless of OS, although I don't have a Mac (let along one before OSX) to try.
On Windows LibreOffice, all that's needed is CHAR(10). CHAR(13) has no apparent effect, other than cluttering the formula.
Mark.