Yes it is true. I see that I have understood the problem described again wrongly. Well, if sndloop wants no pause and the MP3 file has a gap at the end, say 3 minutes lenght and at the end pause 1 second, it can also be solved with one line.
IF _SNDLENGHT (musicloop)> 179 THEN _SNDSETPOS (musicloop), 0. But of course, everyone will do it on their own.