Anyway, the confirmation time tolerance of LOTW is within 30 minutes, so there's no need to worry about accuracy.
Regarding my voice communication, if it's a standard voice transmission or telegraphy, the duration of each connection might be relatively long. Therefore, I calculate based on multiples of five minutes. For example, when communicating with a specific station between 23 and 29 minutes, I would record it as either 25 or 30 minutes. When operating through satellites, there may be multiple QSOs within a short period. I am accustomed to using my phone with the tracking software open + screen recording, and then accurately recording the time when listening back.