I went back and read the rules and it seems unclear.
Perhaps this sentence will help clarify things:
If Band-in-a-Box or RealBand have been used, please provide information as to which styles or RealTracks were used.The "if" allows that not all songs posted will necessarily have styles or RealTracks.
That's my reading of it, anyway. IANAL, YMMV,
et cetera.