i guess the text explains it all.. n reverse sensing is with the 6 and 12 degrees angles.. if u closely look at the diagram, the 150hz lobe lies above these two lines n 90hz lobe lies below them.. so if flying these angles, u are on 6/12 degree false path n u deviate slightly above them then, this will keep showing u to fly UP and similary if u go below its gonna show u to fly DOWN unlike the normal 3 degree or its odd multiples..