Using the DelimitedSplit8K function appears to whip the pants off of the other method.   I couldn't get any duration at all from even a datetime2(7) = SYSDATETIME() computation of DATEDIFF. ...

Have you thought this through?   If you had such a CHECK constraint in place, how would you ever add anything new to the table?   Assuming existing data already added up...

Not that you can't do computation in T-SQL, but if you're looking to put formulas into columns and expect solutions, I'd have to question your judgment skills.   That kind of...

When you join you'll have to CONVERT the nvarchar value to varchar and then to varbinary.

Let's add the displayed data and the code to do it:CREATE TABLE #Table (
    ID int NOT NULL PRIMARY KEY CLUSTERED,
    OrigID int NOT NULL,
    Col1 int NOT NULL,
    Col2...