If 2 passengers (1K and 1K million miles) have exactly the same itinerary and same booking class under 2 seperate confirmation numbers, and they both use the same instrument (systemwide upgrade cert) to apply for an upgrade, does 1KMM has priority over IK?

I happened once I (1KMM) and my staff (1K) were both waitlisted for upgrade, his upgrade was cleared 2 days before departure and mine didn't get cleared until the last 30 minutes at the gate. He requested the upgrade online 10 days before departure and I also did it online but 3 days later than him, so I wonder if 1KMM and 1K are no difference and it is only a matter of timing (if booing classes are the same).

Thanks for any advice.