Higher prices at prime times?
Eh, I feel like you're almost paying a premium to eat early (ie to get a table for the Lincoln Center rush).. If you look at what's offered on the prix fix it's basically $15-20 apps, $30-35 entrees and $10-15 dinner, so you total $55-$70. Not saving much, and you are stuck with a smaller menu and you have to get 3 courses each. With the minimal $ savings, forced ordering, and fewer choices, the a la carte menu seems like a better deal.
I find that most restaurants will offer a discount for off hours (pre theatre prix fixe, happy hour, Savored discount, etc) than to charge MORE for peak hours.
There are at least two restaurants outside of NYC who DO charge more for prime time and weekend tables: Next and Alinea in Chicago.
Next sells out every night regardless of price, due to its seasonal menus (turning menus every 4 months = artificial scarcity) and lower overall price point ($85-110).
But Alinea is another story. If you look on the Alinea site when tables go on sale, the Wednesday and Sunday tables, while cheaper, linger for much longer than the Friday and Saturday tables. And the very early and very late times sell much more slowly than the 7-8pm time slots. Despite being cheaper.
It's very explicit on their site that you're paying a premium for your Saturday 8pm table, and they seem to be doing very well, eventually selling out every night (though it sometimes takes a while).
This is definitely happening at restaurants that sell tickets rather than traditional reservations, such as Alinea, Next, and Elizabeth in Chicago. They equate it to the way theater seats are priced higher on a Saturday night than a Wednesday due to demand. NoMad in New York is using the same ticket system so I assume prices also vary there, but I have not specifically read about their policy.