I may be wrong, but I think you are misinterpreting what it means to be able to "request the upgrade." Granted, it's not worded ideally, but just because you can now "request the upgrade" on day of departure does not mean that said upgrade will be granted immediately upon request. I think what it really means is that you will now be able to go onto an airport standby list when you make such a request.

The issue under the old program was that for international flights you could not even request, much less use, a PMU on the day of departure when no Z inventory was available. Period. The change in the new program is that now you can. As to domestic usage of PMUs, even under the old program I think a PMU could be used on day of departure (just like I know you could use miles on day of departure if you cleared a gate standby list).

So, what they are trying to say, I think, is that things have changed, and you can now request to use a PMU on day of departure even if no Z inventory exists. However, in the absence of Z inventory being available, I don't think you would be cleared into that "available" J seat until the gate lottery takes place.

What is unclear is whether, now or in the future, there is any preference given to those standing by for a G or Z inventory type upgrade as opposed to a V/X inventory type upgrade.

The bottom line is that I just don't think you'll be able to go to the airport at one minute past midnight with PMU in hand and claim an F seat on a domestic flight departing 18 hours later that's showing F2 A0 G0 V0. I think it will go to gate lottery, and if you win the lottery (under whatever rules are established) then you can hand in the PMU.