I got 2 Stars on 50cc Flower Cup, or something. I was going to play the 100cc's and then go back to do the 50cc Flower after that. I 3 Star'd the 100cc Flower, and then when I went to pick 50cc Flower..I magically had 3 Stars. "Did I 3 Star it the first time? Is this my imagination?" No matter, I still had the last top row (Lightning?) that I only 2 Star'd on 50cc. Proceeded in the same manner again for the 100cc, and when I went to pick 50cc, I had 3 Stars there again after 3 Star'ing the 100cc one. Wow!
So yeah. I don't know what the correct verbiage is. My definition, that IS Stars "carrying down."
I'd love to never have to play 50 or 100 in my life, but unfortunately Nintendo forces you to play through all of them. I honestly forget how I do it. Probably start at 150 and then go back when I've had my fun and am ready to do the boring grind.
Stars might only carry down if you achieve a 3 star score. Otherwise I don't think they do.
They carry down regardless. I did four cups on 150cc that I didn't play otherwise and my one star scores carried down. They won't replace a higher score. For example, if you scored two stars on the 100cc Mushroom Cup and then scored one star on the 150cc Mushroom Cup, your 100cc score would still hold for 100cc and 50cc.
@Mr_Mustache It makes perfect sense, because I want to actually enjoy a game during my initial play, not slog through a bunch of stuff that I don't care about. If I have to grind, I'm sure as F not doing it day one.