If the records are anything like those for my phone, they show when the call started and how long it lasted. For billing purposes. So it ain’t hard to come up with a finish time.
I once worked for Sprint Telecom in their customer records and billing division and you are right, the phone companies do have the start, stop, length and more phone call information, but that is not what ABC shows in their photo. ABC implies that there was an ongoing continuous conversation, but the photo only indicates when the calls started and indicates nothing else whatsoever.
So, if the Florida law enforcement folk provide that information to the public, I will then believe the time line. However, I have no reason to trust media that use false or misleading information to boost their ratings.