I usually ask my TA to book "V" class (even if waitlist) then call MPO to confirm booking. Usually takes just a few minutes. If agent is hesitant at first I remind him/her of Gold MPO status and minimum 72-hour seat guarantee, which they would do for at least "V" economy class. I see you are Silver MPO (so seat not guaranteed, I think?), but still worth trying, IMHO. Good luck!