My personal reason for the importance of times of death stemmed from when I worked on the wards when we lost a patient. If at the time,it was sudden and the family weren't around,,they'd be told and their first question would be " what time did he/she die ".
Then their conversations would turn to where they were,or what they happened to be doing at the time their loved ones passed away.
Everything had to be entered,,and it's this part of the botched investigation that I can't get my head around. I would have asked what time each individual had died.