It seems that, no matter if "insert instrument change" is checked or not, when opening a midi file without using the wizard the instrument changes are not imported.
Also the note resolution and rest resolution seem ignored. (This explains why I never had any effect fiddling with those parameters!)
Using the import wizard with the same options does get the "instrument change", but the imported score rhithm is... completely wrong.
Just to be clear, this is without wizard (correct):
!NoteWorthyComposerClip(2.75,Single)
|Clef|Type:Bass
|Key|Signature:C|Tonic:C
|Instrument|Patch:24|Trans:0|DynVel:10,30,45,60,75,92,108,127|Pos:8|Wide:Y
|TimeSig|Signature:4/4
|Rest|Dur:Whole
|Bar
|Chord|Dur:Whole|Pos:3,5,7
|Bar
|Chord|Dur:8th,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=First
|Chord|Dur:64th|Pos:3,5,7|Opts:Stem=Down,Beam
|Chord|Dur:32nd,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=End
|Chord|Dur:Half,Dotted|Pos:3,5,7|Opts:Stem=Down
|Bar
|Chord|Dur:8th,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=First
|Chord|Dur:64th|Pos:3,5,7|Opts:Stem=Down,Beam
|Chord|Dur:32nd,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=End
|Chord|Dur:Half,Dotted|Pos:3,5,7|Opts:Stem=Down
|Bar
!NoteWorthyComposerClip-End
With the wizard (options unchanged):
!NoteWorthyComposerClip(2.75,Single)
|Clef|Type:Bass
|Key|Signature:C|Tonic:C
|Instrument|Patch:24|Trans:0|DynVel:10,30,45,60,75,92,108,127|Pos:8|Wide:Y
|TimeSig|Signature:4/4
|Rest|Dur:Whole
|Bar
|Chord|Dur:Whole|Pos:3,5,7
|Bar
|Chord|Dur:8th,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=First
|Chord|Dur:64th|Pos:3,5,7|Opts:Stem=Down,Beam
|Chord|Dur:32nd,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=End
|Chord|Dur:Half,Dotted|Pos:3,5,7|Opts:Stem=Down
|Bar
|Chord|Dur:8th,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=First
|Chord|Dur:64th|Pos:3,5,7|Opts:Stem=Down,Beam
|Chord|Dur:32nd,Dotted|Pos:3^,5^,7^|Opts:Stem=Down,Beam=End
|Chord|Dur:Half,Dotted|Pos:3,5,7|Opts:Stem=Down
|Bar
!NoteWorthyComposerClip-End