I had this same question and I think you are right, that there may be no standardised answer. From the well-meaning answers given above, though not all seem to be directly helpful, it seems obvious that there is at least confusion.
Writing "Play X times" above the measure is useful for the written score but not for the playback in your transcriptipon software and in that case you need to use the syntax of the software. There may be an option in the 'Tuxguitar' settings which allows you to choose how the multiple repeat function is displayed on the score, but you'll need to google that one. I use GuitarPro and it certainly has the capability to include non functional notes above the score, Eg. lyric cues.
Why not choose to use the same syntax as your software does and then ensure you communicate that with any musicians who will use your score? When there is no agreed upon standard you get to choose your preferred convention in my opinion.
I think of it as: the repeat symbol itself implies the first repeat and the number above the repeat symbol tells you how many extra times you play it; if you play the repeated section exactly twice (i.e repeat once) then you do not indicate it with a "x1" above the score, but if you play it thrice (i.e. repeat twice) then you would indicate that with a "x2" etc...
In the end, I have written a lot of words, but have probably also not been directly helpful!
All the best,
Frank