I got the sense that the guy wasn't that familiar with the roads there.
Especially when he got to the top, he mistakenly went into the garage where the buses and taxis line up and he was worried about getting a ticket. He went out and had to turn back around.
So maybe he honestly got lost and decided to go back down to where he was familiar. He was staring at the Uber app. screen on his phone.
It turned out to be more than double the original fare estimate but overall it was about $7-8 USD more so I'm not going to make a big deal out of it.
On another note, this Uber was a Benz C-class and then I took an Uber early the next morning from TST to Kowloon station for 25 HKD and the woman picked my up in a BMW 520i.
She asked if I wanted to go to the airport but I insisted I wanted to go to Kowloon station since I had a round-trip Airport Express ticket and I wanted to do the in-town check-in of my big suitcase.
I don't know how Uber drivers make money making a few bucks in nice cars.