I recently flew ATL-FRA-BOM on DL. I had a special meal request on my itinerary. Both segments were heavily overbooked. Since I saw a FO being called for an operational upgrade, I went over to a Redcoat and asked why I wasn't offered one (I'm a GM). He indicated that since I had a special meal request, the system automatically "passes over" me. As it turned out, I was able to get upgraded on both segments by telling the agents that I don't really want a special meal if it meant that I won't be getting a upgrade. Interestingly enough, I saw a couple of non-Medallions being upgraded - couldn't tell why.

Can someone tell me what is the priority for operational upgrades and how special meal request affects it?

Thanks!