Some practitioners of timeboxing want the calendar at the end of the day to reflect how time was actually spent rather than how it was planned to have been spent.
This distinction of planned versus actual is really huge to me, which is one of the big reasons I fell in love is Sunsama immediately.
But I think planned time has too much of a spotlight as it is.
Ideally, the Daily Planning ritual should be all about the planned time for tasks, while the Daily Shutdown should be all about the actual time spent (or not spent) on them.
On Daily Planning stage, the tasks should appear on the calendar according to the planned time, but on Shutdown stage, the calendar should be reflective of the execution of that plan. There could even be a way to compare both! (Maybe have the Daily Planning ritual take a snapshot of the calendar state at the end of it, and then show it during Shutdown alongside the current state of the calendar?)