Genghis - now no wriggling, the difference may be small but it doesnt make it any less real. Whether it is significant is academic as that was not the question, just whether there was a difference.
As is so often the case what we do in the real world maybe different for all sorts of reasons - the sailor may follow the magenta line because he couldnt plot a tidal stream if his life depended on it (and yes, they really do exist in this age of GPS), and the aviator may follow the magenta line for other reasons.