I see the confusion! I don't like it. To me, compasses are to tell you which way you are looking. Hence HDG. Tye explanation under 'Map Mode' explains that the diagram is to represent that some people may want an oddball representation of TRK up and it takes a software change to allow TRK up. I would give it no more thought. I shall have a play tonight on the 747-400 and see if it is possible to have it that way but I'm fairly certain it can't even be done (not that you would want to- you have a very effective white TRK line). I reckon that diagram is just to show you that it can be accomplished (with software changes). Give it no more thought other than to the option of HDG (True) (long overwater/polar flights) and HDG (Mag).