As you wrote, it calls exactly. As people filled the order books before sleeping, they do whatever they want. Keep your coins without selling option and do trade when you are on the front of the screen. You will see price will jump extremely...
Think about it: the robots buying up the orders already in the order books, if there is no order to sell, the price getting higher, and the robots buying up constantly on higher and higher prices.....if you have flat currency, check the robot movements and buy in the middle, and keep the coins without selling order. Wait wait....if all do the same in 1 hour the price will be again near 20k$...