If mechanics has not changed from d2 to d2r, in nightmare and hell, area level still determines the item level of the item dropped. But champion monsters drop item level +2, while boss monsters and their pack members drop +3 item levels.
As far as i know, the item level of the grand charm must be over 91, since the "of vita" (41-45 life) suffix has that level requirement. Diablo from hell should also work then, since he has level 94.
When you say terror zone andariel, i'm not sure which zone that is. And i'm not sure which monster type dropped the item.