"In addition to the times stamped on calls by telephone operators, the radio operators stamped the "time" as calls were dispatched, and the "time" that officers completed an assignment and returned to service. Radio operators were also furnished with 12-hour digital clocks to facilitate their time references when they were not using call sheets containing stamped time. These digital clocks were not synchronized with any time standard. Therefore, the time "actual" and time "broadcast" could easily be a minute or so apart." -- J.C. Bowles
For some unknown reason (wait, I do know the reason after all), you keep wanting to stretch this "minute or so apart" to mean six or seven minutes.