The Del Rey is open 24/7 and has girls there 24/7. The price can tend to drop later in the night mostly after midnight but my experience on my last trip (Nov 2011) was that even at 3am they were less easygoing about dropping the price and I was still getting the normal 100 quote even as late as 4 am, but eventually walked out with one in the 60 dollar range. I have spoke with many who don't seem to share the some money is better than none attitude. Example being a cute little girl I was talking to about 3am in the Del Rey starts at 100, I counter with 80 and she laughs and explains she never gets less than 100.
I tell her it's late I will go 80 or pass, she said 100 baby I'm going home soon and need to make money, one last offer of 80 and no go. Watched her get into a cab alone a short while later... I would assume to go home but who knows.