I am now in the process of incorporating the 1840 Morgan County census into the website. This has resulted in a number of cases of adding people to the index who were in Morgan in 1840 but NOT in 1850. They are listed in bolded green to separate them visually from those who WERE in Morgan in 1850. When I get to incorporating 1830 into the website I'll continue to use that format (as well as any even early listings I happen to include). As for people not in the 1850 census but in 1860/later censuses, I'll figure that color scheme out when I get to it!