Thanks, Dan and AudioTrack, for explaining the ledger lines.

Back to BIAB and exporting songs to MIDI the question reamins:
If I have five voices (lanes/tracks/instruments) in a piece (song) and two are octave-shifted and three are not, how do I find out which one?
Is there an indication about it where I can recognize it and sepaate them into shifted (transposed) and not shifted?