[lokar]

Everyone is saying "rounding, duh" but that a bit unfair IMO

You should show each integer value second for, ideally, one second (in the case with no display for fractional seconds). So the question is: exactly what rage of time to cover? The poster expected that for second N, it would be:

[N,N+1)

But Apple seems to do:

[N-0.5, N+0.5)

I think the Apple behavior makes perfect sense when you are displaying the current time (eg like a watch). It may be a little less obviously correct for the timer case, but still seems fine. I'd bet they implemented it for the time of day case and just re-used it for the timer case.

[benzoate]

Well you have 6 numbers and only 5 seconds to show them in. You could show 0 only when the timer has fully completed.

I think either rounding up, or rounding to the closest integer is fine. The authors expectation of always rounding down is the only option I would never expect.

[lokar]

I think people have different expectations for:

"What time is it now?"

vs

"How much time is left?"