This gives me a nostalgic reminder of when I used to watch Nickelodeon GUTS. Whenever a countdown timed challenge was about to end, I would hear the audience count down starting with "10" at maybe 10.7 seconds, "9" at 9.7 seconds, etc. Then after "1", there was a small period of awkward silence and murmurs from the audience before the siren blasted.

It's a good example of how measurement of time in terms of human perception differs from the pure mathematical sense, and rounding is a good compromise here (wherever it doesn't display fractional seconds).