No, there shouldn't be separate entries for synonymous plants. The database is specifically designed to avoid the sort of mayhem that results when synonyms are treated separately.
Codiaeum variegatum var. variegatum is an accepted name and is listed in the database as such. Croton johannis is classified as a synonym of
Garden Croton (Codiaeum variegatum var. variegatum) and the name could certainly be added to the entry. Of course, Codiaeum variegatum var. variegatum seems to have about a million synonyms. I'm not sure how important it is to list them all?
You added as a cultivar of Codiaeum variegatum. If that was your intent, it's fine how it is. However, Croton angustissimus is a synonym of Codiaeum variegatum var. variegatum. If you were trying to add C. angustissimus to the database, then that entry will need to be merged with the Codiaeum variegatum var. variegatum entry. Please let me know what your intent was there.
