rehearse timings

When using “rehearse timings” in Impress, the recorded time is truncated to the nearest second below. When more precise timings are required, this is frustrating, because the times must then be edited by hand. (My actual application is to display the words of a song in time with the music.) Moreover truncation rather than rounding means that the errors are cumulative.

Is there a way around this?

Failing that, it would be a tiny matter for someone to correct this problem. So I guess I am requesting a small mod to this feature.

(LO 5.1.6, Ubuntu 16.04)