It does not work to open a biab file directly from 2019 with Musescore 3 updates, found a tread in Musescore forum that explains the same issues I am finding.
Perhaps a way forward would be to be able to export utility tracks in xml format along the usual tracks, xml imports very well into musescore.

The wish is about being able to make the process more efficient, and biab has got the elements already, it just needs that little extra tool.


Artur