It varies by market. I would think that more PIT-PHL F seats would be made available for upgrades vs. PHL-LAX?

But in your situation, holding 7 of 12 might mean 5 were purchased already, given as award seats, full fare Y customers with cheap upgrades, etc.

Given that, it's not out of the question that this management would hold 100% of the seats back for revenue until the last possible minute.