I have a navionics premium map card ,I have a 788 ci combo ,and a 998 hd si ,it says on the box it has xd contour maps in it ,but I put my navionics in my 998 and just went fishing ,my question is .Is the xd contour map as good as the navionics map should I put the card back in my 788 ,I looked back a few pages and couldn't find any other info on it ...