Did you catch the carpool/cab in the normal time frame? This looks like factory from the times you're giving. If you call a cab and get to the factory around 10, you will often start the last round just before 5 and finish just before 7 due to the 10 minute duration of the rounds. This isn't an extra round, it's just getting started in the nick of time to get a full shift of 4 rounds in.