I think nukecad answered my question with his "perhaps" statement above, but I want to be sure.
I have a number of cookies listed under "Cookies to Keep" and ran a Clean. Now, Health Check indicates that it uses Custom Clean Parameters. The cookies that I want to keep are NOT listed under "Cookies on Computer". This is confusing. Are the cookies that I want to keep, kept? If so, the "Cookies to Keep" are also "on Computer", which I believe is what nukecad was implying.