which of the records has the most recent date. That one gets tagged as "Current" and the others get tagged as "History".
Are you're interested in the related record with the most recent change? That would be much easier to implement as an attribute of the parent record; since only one record can be Current, and all others are by definition History, you only need to capture that record's ID in the parent, and don't have to change/update any child records.
I have a One_cn calculated number = 1, and a G_One_cn global number that = 1 too.
Also see if using a relationship with the Cartesian operator (x) helps here – it does the same as your two fields, just without the need for an additional stored field.
Not the record with the most recent change; the record with the latest Date.
I had initially used the X operator, but by doing it with a global field I can use the same script when I delete a record.