This is a great question. Searching for an answer but could not find so I ran some observational testing between Video.JS and HLS with start and end time.

So far my experience is that HLS files will not playback at a precise timestamp.

Say you request:

m3u8?asset_start_time=5.0&asset_end_time=38.0

Video.JS will round the start time and end time down* to the nearest [encoded] segment.

*observational, there may be a precise answer.