Award seats and revenue management ...

Hi fellow v-flyers
Please excuse the newbie question that I have but I have searched the forum and can't seem to find an answer.
Is there any logic/pattern to when revenue management releases more award seats on a flight? Like do they release seats more often on one day of the week than others or do they do it X number of days before departure?
I am flying SFO->LHR June 2 and returning LHR->LAX on June 17 in PE (on a reward ticket) but I would like to upgrade the LHR -> LAX leg to Upper and when I call the agents keep saying just check back for availability. Expertflyer was showing 9's across the board for the flight so it is apparently very open.
Thanks for the help.

Please excuse the newbie question that I have but I have searched the forum and can't seem to find an answer.
Is there any logic/pattern to when revenue management releases more award seats on a flight? Like do they release seats more often on one day of the week than others or do they do it X number of days before departure?
I am flying SFO->LHR June 2 and returning LHR->LAX on June 17 in PE (on a reward ticket) but I would like to upgrade the LHR -> LAX leg to Upper and when I call the agents keep saying just check back for availability. Expertflyer was showing 9's across the board for the flight so it is apparently very open.
Thanks for the help.