7800 games... NES sprites???

[procyon]

I was playing some of the Nintendo created 7800 games (DK, DK Jr., MB) and I noticed the similarity between the sprites used on the 7800 and those used in the same games on the NES, and I was struck by the similarity between them. I was always pissed that Nintendo didn't do a perfect sprite conversion of Mario Bros., and instead chose to alter the graphics of the turtles. So the design of those sprites are burned in my mind. Then all of a sudden when I started playing MB on the 7800, there they were again, the exact same altered sprites. Not only that, but the altered placement of the pipes were exactly the same on the 7800 as they were on the NES, compared to the arcade. So I started looking at other games where Nintendo altered the sprites from the arcade to the NES conversions, and comparing that to what the 7800 had. Another example I found was the snappers in DK Jr. In the arcade they're much thicker, and on the NES, they're very thin. Sure enough, on the 7800, it's the exact same problem. I realize the chances of anyone having information on this is small, but... does anyone have any information?