Where was the 8 second call there?
It didn't hit 15. They have to wait until the shot clock hits 15 to ensure they get the full 8 seconds before crossing the half line.
It's 16. 15 would be 9 seconds.
No, I'm sure the practice for the refs is that they wait until as soon as it hits 15 on the shot clock. The logic is then that gives them the full 8 seconds to cross over. If they called it as soon as it hit 16, then it wouldn't be the full 8 seconds, but somewhere between 7 and 8 seconds.