I've had that happen for both MNSSHP & MVMCP. I've learned to always call back when in doubt.
When I called to book LTT for MNSSHP this year, I was told the 1st seating was all booked. Yet, when I redialed and got another CM, I was about to get PS for 5:05 the night I wanted. Makes me wonder if the first one even bothered to check .
The first two times did you tell them you already had your MNSSHP tickets?
Last year, we got the tickets first, then decided where to eat. When we called back to get PS, at first she said no, 60 days. But then I gave her the confirmation # for our MNSSHP tickets and she was able to book it.
This year I just did it all at once. The girl that reserved our tickets for MNSSHP made the PS for LTT. She read off the list of times available and I picked. We are going Oct 5th and our PS for LTT is at 5:10.