You have to keep in mind that turning off your scoot and ending your ride are two different operations:
You turn off the scoot when, for example, you need to run an errand and you don't want to end your ride and reserve another one later. Here, you only have to long-press the go button (the red one on the right part of the handlebar) until you see that scooter turns off. You also have the option to click on "turn off" and you will see a message asking you if you want to end the ride or just turn off the scoot. Remember that the billing counter doesn't stop until you end the ride.
If you want to end the ride, you only have to click on "turn off" in the app and when you see the message asking you if you want to end your ride click on "yes, end my ride".