[Timer Start] When the timer shows 0.05, the edge of Course 21 is not yet red. This means the timer starts at least 0.05 seconds faster.

[Timer Stop] Timing ends when the pop-up after course 30 is visible at the bottom of the screen. At that time, the timer shows 1:36.46.

1:36.46 - 0.05 = 1.36.41, and rounding it, I got 1:36.4