@T**
this is correct in my experience, you usually don't have to wait so much to apply if you turn up later. Unlikely to be "no-one" in line these days but perhaps less. This is what I used do years ago all the time, I would just turn up before they closed.
BUT it is worth bearing in mind that they now issue numbers on application and hand the passports back the next day in the same order that the applications came in. It used not be like this- the queue the second day used depend on when you turned up the second day. Now it depends on the order you applied the first day.
So if you apply late the first day you will get your passport back late the second day- which may or may not matter to you, but if you need to get back to Udon for a flight or whatever you might want to be in the first 400 applying the first day. They hand them back at a rate of approximately 200 per hour so if you are #400 you can expect to get out by 15:00... but if you are #800 that might be more like 17:00.