Before I create a song in Band in a Box (BIAB) I frequently create a very detailed Jazz lead sheet using MuseScore3. When I'm satisfied with the accuracy of lead sheet, I export it into a MusicXML file (which includes chords, and sometimes melody and lyrics).

Invariably, when I import the chords from the MusicXML file into BIAB there are errors in some of the chords. It appears that Band in a Box is converting ALL major 7 chords to dominant 7 chords. For example, BbMaj7 (or "BbJ" shortcut) is interpreted as Bb7 by BIAB. This happens regardless of whether I use "Open Special" or "Import." I can view the MusicXML file in a plain text editor, and it appears that the chords are correct there.

The "Simple Arrangement" option is unchecked in BIAB. I have to manually go through every measure of the song in BIAB and correct all the errant chords manually. Is there a way to remedy this behavior?