One of the reasons i never use MTEXT unless i realy have a big piece of (multilined) text.
Never ever use it for "text-strings" like these.
The last thing i want is people formatting the text, as has been done here, overruling the textstyle.
Since that's exactly what you have here:
\W0.7000 = Set text width to 0.7
\W0.7360 = Set text width to 0.736
\H30.0000 = Set text height to 30
\Ftxt = Set Text Font to txt (.shx)
etc.
Especially the various, slightly deviating width settings is something i would not accept, from myself or any colleague. ...but ofcourse you can do as you please. Just mind the consequences (which is: extra formatting info with your MTEXT content)
If you used TEXT, not MTEXT and applied a textstyle (with width set to 0.7 if that's what you want), you would not have this problem right now.
Looking at the image & export; it appears to me you used MTEXT where a block with attributes would fit 10x better. You may have your reasons, but you are making it hard on yourself this way.
In the end, you do not want to extract the data, but only a part of it.
For that you will need to write a lisp.
One that will take the MTEXT and remove all the formatting, before exporting. (you can probably find a lisp right here on the forum to do just that)
BTW: I'm not trying to bash you or something, just saying:
Had you used regular TEXT or, better yet, a block with attributes (where you can still apply different formatting with each attribute), you wouldn't be having this problem.