Originally Posted by SeeBuyFly

Based on the language you used ("J fare", "purchase"), I am assuming that you are NOT talking about an award, but about a paid ticket. Why should people who have bought Y be automatically moved up if J becomes available? That would be crazy--most people buy Y and have no desire to pay for J.

Now with an award, it is possible to take a 'voluntary' downgrade on some segments while paying the full amount of miles for a J award. In those cases, it would be nice if they would fix the issue automatically hen there is availability. But there is nothing in your post that suggests you are talking about awards.