It sounds like you fly this route pretty regularly and have been doing it for a while now. You are probably a better judge than most people here. As a GM, when you don't get upgraded, how close are you to the top of the list? What fares are you flying on? If you are T or U fares and you are usually only a few off from getting an UG, then chances are good that you'll get more UG's as a PM. If you are typically 10+ back for 1-2 available seats then chances probably aren't so good for more upgrades.