Couple of observations.
1) Flew a RT last weekend & today. Looking like 0/4 on upgrades - at the top of the list but didn't make it. A lot of this seems to be fliers > capacity
2) comments saying F is just a little more than Y have me perplexed. I'm certainly not seeing that. When I price F, I'm getting F = ~2X coach. Maybe a lot depends on what routes you're talking about...