Yep that was my experience too, as soon as I made Signatures reservation, then the rest of the nights only showed Latitudes - it says somewhere when you first click on the link that you can only make one specialty reservation per booking per restaurant - so as above, the only thing I could do after that was Latitudes, which I did for the last night. And, I think that once a certain capacity of pre booking for each restaurant on a given night is reached then it closes out, so that they still have some available for gold/platinum, and onboard bookings.