Hi guys

I've recently purchased Tab Pro on the iPod touch. It's a really fantastic piece of software and I'm loving it, but I have one question. On some tabs notes are being played by the midi that aren't on the tab board. They are clearly meant to be in the song but I can't see them. Examples are Dire Straits' Romeo and Juliet and Townes Van Zandt's Pancho and Lefty. Is there something I'm missing out on here in the settings? I've checked and they aren't on the other instruments tab sheet either