One of my pet peeves is when a restaurant doesn't honor their hours of operation. My boyfriend and I came at 10pm after our movie on a Sunday with much enthusiasm because we were in the area where many restaurants had already closed. Since they open until 10:30pm, we wanted to grab a quick dinner but they told us that they weren't taking any more customers.
We could understand that it would be annoying to accommodate within the half hour in case we stayed longer than 10:30. So we asked if we could get takeout since we had made the trip. They said the kitchen was already closed.
If the kitchen closes at 10pm, you should adjust your restaurant hours accordingly to reflect that.