It is impossible to say for sure, but both of the reservations I have found by clicking the actual times. I ran back and forth clicking lunch/dinner on my desired dates for about two minutes straight, then Ran down the times individually. Nothing showed up when I clicked “lunch” but 1-2 seconds later it found one. This happened again when I decided I wanted to change times, exactly the same. Ironically they were both for 2:45. It’s impossible to know if the reservation just happened to become available between the seconds I clicked “lunch/dinner/11am” however, given that it happened twice it has left me a bit perplexed and wondering if the time search is more efficient somehow. Doesn’t really make sense to me, but there it is.