Yes, Brahma, perfect sense and a logical question. No on the difficulty and rating. Some of the courses play easier and it is the topic of great conversation about playing the easy ones to force a tier change. Not a good move so for the most enjoyment play whatever you feel in the mood for. You really should master them all and have fun learning to do it.
As for that Seattle DMM guy, well if I were you I wouldn't post those scores. The sandbagger headhunters would be all over your butt. LOL Besides, that falls under ranked rounds anyway. ;-P