Has it yet been established that the "TRUE"s never change and that this column being static is acceptable?

Except for the code that inserts the new column, that's of no real consequence, as re-running the macro will update everything. Indeed, it would be possible to make an event-driven version of the code, so it runs automatically on any row that does get changed. Such a macro's execution would be far quicker than leaving Excel to recalculate 50000+ rows.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Good points macropod I appreciate the statistics and feedback you provided. I need to update my code to get that last part now.