That's not a date wheel. It's a 10 minute totalizer. When the chrono starts up, the totalizer starts counting down. The wheel shows the numbers in half increments starting at 10. It goes 10, 9 1/2, 9, 8 /12, etc.... down to zero. When the chrono is reset it goes back to 10.
This of course will not be a function that works on my watch as the only way to do it would be to have the gen B36 movement. I will fake it so it will always show 10 like the gen when it's "zeroed"