It shouldn't matter how the OP receives their PM status (as we know they give out Medallion status to people who have flown far less than the OP).

In any case, it is likely that the companion on your reservation caused you to not clear at your window. As was mentioned before a non-status companion on the same reservation will move you to clear at the 24 hour mark not the 5 day mark as you would with a PM. You could have split your record so that you cleared at the 5 day window why your companion cleared at 24 hours. This would have allowed at least one of you a better chance at sitting in F.

Delta has two different inventories for first, F and V. F is the total number of seats available while V is the upgrade seats. Generally F > V as Delta does not like to give the whole F cabin away until they have had every opportunity to sell those F seats to a last minute passenger. Also by saving a few for the gate it gives those Medallions who have changed flights or experience IROPs a chance at a gate upgrade.