I'll give you a minute. Complicated?
The deal is that if you buy a ticket for tomorrow you can see the sunset for free today. My sunsets are usually free but not at Angkor Wat apparently. So you can buy tomorrows ticket at 4:45pm and then go and see it the sun go down. The best location for this is at temple Phnom Bakheng which is on a hill. Riding to the hill takes 15 minutes. Hiking up it the same. They close the hill at 5:30pm, the sun sets at 17:45.
Do you see anything wrong in this logic?