Agree, I'm sure if anyone wanted an 8.30 or even 8pm slot could go when ever they want, a lot have left by then. The 6.30 to 7 ish seem most popular and would be hard to get more than your "ration" .
We've also started going to speciality restaurants on formal nights, if you have an officer hosted table near you in main dining room, they get all the attention, other tables can wait for ages. 😦 Butler had no trouble getting extra reservations.