60K items where duped and 54K items are on the banned accounts. Wouldn't it be interesting to test out to delete all items duped items first on the accounts of the banned and rescan the remaining 6K items how they will be flagged when you delete the 54K items first?
The 54K duped items on the account of the banned can be considered 100% duped
Items crafted by the banned that are on the dupe list can be considered 100% duped
You can still flag the remaining 6K items, but you can't ignore the fact it would be an interesting test to see if they still popup as being duped. I know for a fact that several of these remaining items are 100% legit and show up as a false positive because a sister items was duped. The admins can still decide on a later date to delete or to save those items.